Astro 2020 white papers
AuthorInstitutiontitle/linkDescription
Aalto,SusanneChalmers University of Technology, SwedenExtremely obscured galaxy nuclei – hidden AGNs and extreme starbursts
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Understanding the evolution of galaxies and galaxy nuclei requires studying the extremely obscured activity that has recently been uncovered using submm facilities. Properly interpreting these observations requires advances in the radio, mm/submm, far-infrared and X-ray facilities than can peer through the obscuration.
Airapetian,VladimirNASA GSFC and American University, DCReconstructing Extreme Space Weather From Planet Hosting Stars
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The goal of this white paper is to identify and describe promising key research goals to aid the theoretical characterization and observational detection of ionizing radiation from quiescent and flaring upper atmospheres of planet hosts as well as properties of stellar coronal mass ejections (CMEs) and stellar energetic particle (SEP) events.
Ajello,MarcoClemson UniversitySupermassive black holes at high redshifts
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MeV blazars are the most luminous sources in the Universe and host supermassive black holes. An MeV survey will detect >1000 of them up to z > 5. This would allow us: to probe the formation and growth of massive black holes at high z; to pinpoint the emission region location in blazars; to determine the interplay of accretion and black hole spin.
Ajello,MarcoClemson University, USAThe MeV Background
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The emission of our Universe at MeV energies is unknown. New measurements of the intensity and the angular fluctuations of the MeV background will allow us to constrain models of SNIa formation, the evolution of radio-loud and radio-quietAGN, the growth of the most massive black holes and to constrain the cross-section for dark matter interaction
Albert,AndreaLos Alamos National LabSearching for Sources of TeV Particle Dark Matter in the Southern Hemisphere
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Many promising models hypothesize that dark matter is a particle that can annihilate or decay and produce secondary gamma rays. The Southern Hemisphere is home to many key dark matter targets. A wide field of view survey observatory is needed to probe the many dark matter targets in the Southern Hemisphere.
Alvarez,MarceloUniversity of California, BerkeleyUnique Probes of Reionization with the CMB:From the First Stars to Fundamental Physics
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Much of reionization remains hidden from view, and along with it our understanding of howstars, black holes, and galaxies first emerged. We outline the discoveries enabled by the CMB and highlight the most difficult challenges, including planning and coordination, frequency coverage, angular resolution, and sensitivity.
Anderson,LorenWest Virginia UniversityHII Regions and the Warm Ionized Medium
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Plasma of temperature 10,000K is created by OB stars and takes the form of discrete HII regions and diffuse gas. It is the key to determining the impact of massive stars on the interstellar medium (ISM) and the lifecycle of ISM gas. We review research this plasma, highlight outstanding questions, and provide recommendations for future facilities.
Apai,DanielUniversity of ArizonaMapping Ultracool Atmospheres: Time-domain Observations of Brown Dwarfs and Exoplanets
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Ultracool atmospheres (brown dwarfs, directly imaged exoplanets, close-in and transiting gas giants) are at one of the forefronts of modern astrophysics. We describe the key challenges to understanding ultracool atmospheres and the importance of time-domain observations (indirect spatial information) to address these challenges.
Apai,DanielUniversity of ArizonaPlanetary Habitability Informed by Planet Formation and Exoplanet Demographics
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Many parameters that influence the habitability of a given exoplanet can not be measured. We discuss how can contextual knowledge on exoplanet population and planet formation be combined with uncertain information on individual planets. We review key questions that must be addressed to improve the predictive power of planet formation models.
Appleton,PhilipCaltechWarm H2 as a probe of massive accretion and feedback through shocks and turbulence across cosmic time
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We discuss the importance of the direct detection of molecular hydrogen (through redshifted mid-IR lines, and UV absorption) at high redshift as a probe of massive accretion and feedback processes in galaxies and protogalaxies and to potentially detect gas cooling and feeding the most massive and metal-free dark matter halos to z = 12.
Arney,GiadaNASA Goddard Space Flight CenterThe Sun-like Stars Opportunity
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We describe how terrestrial planets in the habitable zones of Sun-like stars (i.e. FGK dwarfs) offer the best chance of discovering planets with conditions and evolutionary histories analogous to Earth’s, as well as the best opportunity to detect unambiguous biosignatures.
Baker,JohnNASA Goddard Space Flight CenterMultimessenger science opportunities with mHz gravitational waves
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We review opportunities for multi-messenger science breakthroughs involving mHz gravitational waves with electromagnetic observations.
Bardalez Gagliuffi,DaniellaAmerican Museum of Natural HistorySubstellar Multiplicity Throughout the Ages
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In this white paper, we advocate for a comprehensive characterization of the multiplicity properties of the substellar population as a function of age to constrain their formation and evolution, particularly across the deuterium burning boundary.
Barnes,RoryUniversity of WashingtonGeoscience and the Search for Life Beyond the Solar System
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The discovery of an inhabited exoplanet is predicated on a robust understanding of its interior. Here we describe the requirements to develop that understanding.
Barstow,MartinUniversity of LeicesterWhite dwarfs as probes of fundamental astrophysics
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Important topics that rely on studies and observations of white dwarfs but provide insight into other areas of astrophysics.
Bastian,TimNational Radio Astronomy ObservatoryRadio Observational Constraints on Turbulent Astrophysical Plasmas
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Using radio observations of background sources, scattering phenomena may be used to characterize the properties of foreground turbulent plasma. We discuss the potential of such techniques to explore turbulence in the solar wind and interstellar medium. The Next Generation VLA will be an ideal instrument to exploit these techniques.
Bastian,TimNational Radio Astronomy ObservatoryDiagnostics of Space Weather Drivers Enabled by Radio Observations
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The Sun is an active star that can impact the Earth, its magnetosphere, and the technological infrastructure on which modern society depends. Radio emission from space weather drivers offers unique diagnostics that complement those available at other wavelengths. We discuss the requirements for an instrument to enable such diagnostics.
Bastian,TimNational Radio Astronomy ObservatoryRadio, Millimeter, Submillimeter Observations of the Quiet Sun
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We point out the lack of suitable radio observations of the quiet Sun chromosphere and corona and outline requirements for next generation instrumentation to address the gap.
Basu,KaustuvUniversity of Bonn"SZ spectroscopy" in the coming decade: Galaxy cluster cosmology and astrophysics in the submillimeter
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A white paper to describe the importance of submillimeter observations for accurate spectral modeling of the SZ effect and how this can transform astronomical research within the coming decade. We highlight some of the main science areas to be impacted by SZ spectral studies and outline the instrumental requirements.
Basu-Zych,AntaraUMBC/CRESST, NASA/GSFCCooking with X-rays: Can X-ray binaries heat the early Universe?
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X-rays from high mass X-ray binaries within the first primordial galaxies likely played a significant role in heating the early Universe at z>10. Combining observations from next generation X-ray telescopes with upcoming measurements of the cosmic 21-cm signal will have the power to offer important insights into conditions in the early Universe.
Battaglia,NicholasCornell UniversityProbing Feedback in Galaxy Formation with Millimeter-wave Observations
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The next decade of mm-wave observations will transform our understanding of galaxy formation, driven by precisely measuring the thermodynamic properties of ionized gas, using the cosmic microwave background as a ``backlight''.  These observations will probe gas well into the outskirts of hitherto-unexplored high-redshift, low-mass systems.
Battistelli,Elia StefanoPhysics department, Sapienza, University of Rome, ItalySunyaev Zel'dovich study of filamentary structures between galaxy clusters
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The Sunyaev Zel'dovich effect measurement of the inter-cluster region between galaxy clusters would be fundamental for the study of filamentary structures and missing baryons in our Universe. We argue that a bolometric camera observing at ∼3mm coupled to a 50−100m class radio telescope is the ideal instrument to disentangle different scenarios.
Bauer,JamesUniversity of MarylandPlanetary Science with Astrophysical Assets: Defining the Core Capabilities of Platforms
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We describe a uniform set of basic capabilities to maximize the yield of Solar System science with future Astrophysics assets while allowing those assets to achieve their Astrophysics priorities. Inclusion of capabilities that make a particular platform useable to planetary science provide a critical advantage over platforms lacking them.
Beaton,Rachael LPrinceton UniversityMeasuring the Hubble Constant Near and Far in the Era of ELT's
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Despite great progress, controversy remains regarding H0. New techniques for measuring H0 have come-of-age in this decade. In the next decade, the combination of ELTs and other ground-based facilities using these techniques will transform measurement of H0. The techniques are described, with a focus on how to realize a 1% measure of H0 with each.
Bechtol,KeithUniversity of Wisconsin-MadisonDark Matter Science in the Era of LSST
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We summarize astrophysical observations that can constrain the fundamental physics of dark matter in the era of LSST. We highlight theoretical work and observational facilities that will complement LSST. Astrophysical observations will guide other experimental efforts while probing unique regions of dark matter parameter space.
Becker,GeorgeUniversity of California, RiversideStudying the Reionization Epoch with QSO Absorption Lines
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We present opportunities over the coming decade for using QSO absorption lines to study the epoch of reionization. We emphasize the role of optical and near-infrared spectroscopy with ELTs and JWST, and note synergies with QSO surveys, redshifted 21 cm experiments, and galaxy studies with ALMA, JWST, and WFIRST.
Behroozi,PeterUniversity of ArizonaEmpirically Constraining Galaxy Evolution
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Empirical models of galaxy formation have demonstrated both significant successes and significant promise for the next decade.
Beichman,CharlesNASA Exoplanet Science Institute, IPAC, JPL/CaltechDirect Imaging and Spectroscopy of Exoplanets with the James Webb Space Telescope
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Coronagraphic imaging and direct spectroscopy of young planets with JWST will add new insights into our understanding of the formation and evolution of exoplanets. This paper focuses on how JWST will add to our knowledge of young giant planets located at orbits beyond a few AU for the closest stars and a few 10s of AU for more distant ones.
Belikov,RuslanNASA Ames Research CenterDirect Imaging of Exoplanets in Nearby Multi-Star Systems
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Binary star systems can enhance the science output of almost any space mission that directly images exoplanets, if the technologies to suppress starlight in multi-star systems are matured. We describe the science benefits and opportunities of adding binary stars to such missions, as well as the key technology advances needed.
Bellini,AndreaSpace Telescope Science InstituteScience at the edges: internal kinematics of globular clusters' external fields
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The outer regions of globular clusters (GCs) can enable us to answer many fundamental questions. The outskirts of GCs are still uncharted territories observationally. A very efficient way to explore them is through high-precision proper motions of low-mass stars over a large field of view. To do this, WFIRST represents the best observational tool.
Bellovary,JillianCUNY - Queensborough Community College and American Museum of Natural HistoryWhere are the Intermediate Mass Black Holes?
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Observational evidence has been mounting for the existence of IMBHs, but constraining their masses is very challenging. IMBHs likely exist in dwarf galaxies, as well as wandering in massive galaxy halos. LISA will demystify IMBHs by detecting their mergers out to extremely high redshifts while measuring their masses with extremely high precision.
Bendek,EduardoNASA Ames Research CenterTHE VALUE OF ASTROMETRY FOR EXOPLANET SCIENCE
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We describe the scientific importance of measuring exoplanet masses and how high-precision astrometry can be utilized for this purpose. We describe current technology development efforts and astrometry missions concepts being proposed by the community to detect and characterize exoplanets.
Bennett,DavidNASA Goddard and University of MarylandWide-Orbit Exoplanet Demographics
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There is currently a gap in our understanding of wide-orbit planets, which must be filled if we are to understand planet formation and exoplanet habitability. We summarize current and planned exoplanet detection programs using a variety of methods: microlensing (including WFIRST), radial velocities, Gaia astrometry, and direct imaging.
Berea,AnamariaUniversity of Central FloridaThe Promise of Data Science for the Technosignatures Field
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This paper outlines some of the possible advancements for the technosignatures searches using the new methods currently rapidly developing in computer science, such as machine learning and deep learning, as well as a couple of case studies of large research programs where such methods have been already successfully implemented with notable results.
Bergin,EdwinUniversity of MichiganThe Disk Gas Mass and the Far-IR Revolution
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Planet formation is one of the major areas where significant growth is expected in the coming decade. A major missing piece is our lack of knowledge of the planet forming disk's gas mass. This white paper discusses how we can make a significant advance in this area and aid countless subsequent studies with grounding knowledge of the total mass.
Berry,ChristopherNorthwestern UniversityThe unique potential of extreme mass-ratio inspirals for gravitational-wave astronomy
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EMRIs are a prime source for LISA. They will tell us about the stellar dynamics in galactic nuclei and massive black hole populations. They will enable percent-level measurements of the multipolar structure of massive black holes and tests of the strong-gravity regime. They may also provide cosmographical data about the expansion of the Universe.
Berti,EmanueleJohns Hopkins UniversityTests of General Relativity and Fundamental Physics with Space-based Gravitational Wave Detectors
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Low-frequency gravitational-wave astronomy can perform precision tests of general relativity and probe fundamental physics in a regime previously inaccessible. A space-based detector will be a formidable tool to explore gravity and some of the greatest mysteries in physics and astronomy, such as dark matter and the origin of the Universe.
Betancourt-Martinez,GabrieleInstitut de Recherche en Astrophysique et Planétologie (IRAP)/CNRSUnlocking the Capabilities of Future High-Resolution X-ray Spectroscopy Missions Through Laboratory Astrophysics
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This White Paper highlights several science drivers for future high-resolution X-ray spectroscopy missions and identifies corresponding laboratory astrophysics improvements required to properly address them.
BHATTACHARYA,APARNAUniversity of Maryland College ParkMasses and Distances of Planetary Microlens Systems with High Angular Resolution Imaging
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Microlenisng is only method to detect and measure mass of wide orbit, low mass, solar system analog planets. Mass measurements of these planets vis high res obs yield massive science. We show that high res obs with AO, HST and JWST remain necessary to enhance the scientific yield of WFIRST microlensing survey.
Binns,WalterWashington University in St. LouisUltra-heavy cosmic-ray science: Are r-process nuclei in the cosmic rays produced in supernovae or binary neutron star mergers?
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Galactic cosmic rays play an important role in the dynamics of matter and magnetic fields in the interstellar medium, and probably also in star formation. There is an opportunity during the coming decade to answer these questions by measuring the relative abundances of every individual element heavier than iron, including the actinides.
Blakeslee,JohnGemini ObservatoryProbing the Time Domain with High Spatial Resolution
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This white paper discusses science opportunities enabled at the interface of JWST and LSST, that is, at the frontier of high spatial resolution time-domain optical-IR astronomy. It describes the capabilities of a practical system that would maximize the science return in this area.
Blecha,LauraUniversity of Florida, Gainesville, FL, USADetecting Offset Active Galactic Nuclei
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Gravitational wave (GW) and gravitational slingshot recoil kicks can produce active galactic "nuclei" that are offset from the centers of their host galaxies. We highlight opportunities to detect offset AGN with future telescopes and describe how these observations would provide key constraints on SMBH binaries and GW event rates.
Bogdanov,SlavkoColumbia UniversityDetermining the Equation of State of Cold, Dense Matter with X-ray Observations of Neutron Stars
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X-ray observations from multiple next-generation X-ray telescopes proposed for deployment in the 2020s and beyond, using several complementary techniques that require different combinations of high time resolution, superb spectral resolution, and high spatial resolution can provide definitive constraints on the state of cold, ultra-dense matter.
Boice,DanielScientific Studies and ConsultingUnderstanding Activity in Small Solar System Bodies
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Gas and dust activity in small Solar System bodies is essential to understanding the clues that these objects hold concerning the conditions of the early Solar System. However, many important questions remain about the mechanisms of activity, including outbursts. We propose several research pathways to address this lack of knowledge.
Bolatto,AlbertoUniversity of Maryland at College ParkCold Gas Outflows, Feedback, and the Shaping of Galaxies
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This paper outlines several key open questions on galaxy outflows, particularly cold outflows, and the associated feedback. After laying out the questions we briefly discuss the requirements of the observations necessary to make progress, and the relevance of several existing and planned facilities.
Bonifacio,PiercarloGEPI, Observatoire de ParisExtremely metal-poor stars: the need for UV spectra
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Extremely metal-poor stars are the fossil record of the gas in the pristine Universe. They offer us the opportunity to understand the mass distribution and nucleosynthetic properties of the First generation of stars. UV spectra provide access to information not available in other spectral ranges.
Bower,GeoffreyASIAAFundamental Physics with Galactic Center Pulsars
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Pulsars in the Galactic Center are important probes of General Relativity, star formation, stellar dynamics, and stellar evolution, the ISM, and the supermassive black hole accretion flow. A pulsar in orbit around Sgr A* will characterize black hole physics and GR at sensitivities orders of magnitude better than any other method.
Bowler,BrendanThe University of Texas at AustinThe Demographics and Atmospheres of Giant Planets with the ELTs
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Fundamental questions about the system architectures, formation, migration, and atmospheres of giant planets have been unanswerable with the current generation of ground- and space-based facilities. This white paper highlights the scientific potential of the ELTs to address these questions with a focus on direct imaging of Gaia-selected planets.
Braatz,JamesNRAOH2O Megamaser Cosmology with the ngVLA
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A local measurement of the Hubble Constant at z << 0.5 provides the strongest complement to observations of the CMB for constraining models of dark energy and testing the standard cosmological model. This white paper describes how the ngVLA can contribute to measuring H0 to a precision of one percent using the H2O megamaser method.
Bradac,MarusaUC DavisSpectroscopic Probes of Galaxies at the Epoch of Reionization
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While JWST will revolutionize the study of galaxies at the epoch of reionization, several questions will remain unanswered even after the data is taken. ELTs will provide a comprehensive picture on the properties of Lyman-alpha emitters, and establish them as one of the main probes of the reionization epoch.
Brandt,TimothyUniversity of California, Santa BarbaraRealizing the Promise of High-Contrast Imaging: More Than 100 Gas-Giant Planets with Masses, Orbits, and Spectra Enabled by Gaia+WFIRST Astrometry
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This white paper identifies absolute astrometry by Gaia and WFIRST-WFI as a powerful complement to ground-based imaging. A shallow, full-sky WFIRST survey could calibrate Gaia's data products and discover and weigh ~160 planets that can be imaged by 30-m telescopes.
Bregman,JoelUniversity of MichiganA Survey of Hot Gas in the Universe
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A large fraction of the baryons and most of the metals in the Universe remain unaccounted. Their kinematic signatures hold critical insights to the processes of galaxy formation in extended group halos, galaxy groups, and the cosmic web. We present why grating spectrometers are essential instruments for future X-ray missions.
Brightman,MurrayCalifornia Institute of TechnologyBreaking the limit: Super-Eddington accretion onto black holes and neutron stars
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We discuss the phenomenon of super-Eddington accretion onto black holes and neutron stars, which has key cosmological importance. We argue that sensitive broadband X-ray observations, especially above 10 keV, are required to study this process.
Brown,PeterTexas A&M University, Mitchell Institute for Fundamental Physics and AstronomyKeeping an Ultraviolet Eye on Supernovae
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Transient astronomy will take another leap forward with the wide-field samples from LSST and WFIRST. It is imperative that we plan for ultraviolet capabilities to maximize our understanding of these explosions, their use as cosmological probes, and for comparisons with high redshift supernovae in the early universe.
Bryson,SteveNASA Ames Research CenterMaking Exoplanet Surveys Useful for Statistical Population Studies
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In this white paper we discuss what kind of information surveys can provide to facilitate statistical analysis that reveals properties of true exoplanet populations. We will gather lessons from various surveys and discuss how diverse and independent surveys can provide data that supports statistical inference. We make several recommendations.
Bulbul,EsraCenter for Astrophysics | Harvard & SmithsonianProbing Macro-Scale Gas Motions and Turbulence in Diffuse Cosmic Plasmas
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Cluster outskirts provide crucial information on the assembly and virialisation processes of massive dark matter haloes and cosmology. This paper provide future prospects for measurements thermodynamic and kinematic properties of the intracluster medium in faint regions of galaxy clusters with forthcoming planned X-ray and SZ observatories.
Burchett,JosephUniv. of California - Santa CruzUltraviolet Perspectives on Diffuse Gas in the Largest Cosmic Structures
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In this White Paper, we highlight key science cases where UV spectroscopy will provide unique insights into the most massive structures in the Universe, and we discuss how current (HST/COS) and future (LUVOIR) missions can deliver transformative understanding of galaxy evolution, galaxy cluster physics, and gas within the Cosmic Web.
Burgarella,DenisAix-Marseille University, CNRS, CNES, Laboratoire d’Astrophysique de MarseilleMeasuring the Metallicity of Low-Mass, Low-Metallicity Galaxies in the Early Universe and the Galactic Habitability
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This White Paper describes a science case related to the Measuring the Metallicity of Low-Mass, Low-Metallicity Galaxies in the Early Universe and the Galactic Habitability and how to gain access to the necessary measurements.
Burgasser,AdamUC San DiegoFundamental Physics with Brown Dwarfs: The Mass-Radius Relation
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The lowest-mass stars, brown dwarfs and giant exoplanets span a minimum in the mass-radius relationship that probes the fundamental physics of extreme states of matter, magnetism, and fusion. This White Paper outlines scientific opportunities and the necessary resources for modeling and measuring the mass-radius relationship in this regime.
Burgasser,AdamUC San DiegoHigh-Resolution Spectroscopic Surveys of Ultracool Dwarf Stars & Brown Dwarfs
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High resolution spectroscopy of the lowest-mass stars and brown dwarfs reveals their origins, multiplicity, compositions and physical properties, with implications for the star formation and chemical evolution history of the Milky Way. We motivate the need for high-resolution, infrared spectroscopic surveys to reach theses faint sources.
Burns,JackUniversity of Colorado BoulderDark Cosmology: Investigating Dark Matter & Exotic Physics in the Dark Ages using the Redshifted 21-cm Global Spectrum
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The Dark Ages, probed by the redshifted 21-cm signal, is the ideal epoch for a new rigorous test of the standard ΛCDM cosmological model. Divergences from that model would indicate new physics, such as dark matter decay (heating) or baryonic cooling beyond that expected from adiabatic expansion of the Universe.
Burns,EricNASA GoddardA Summary of Multimessenger Science with Neutron Star Mergers
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The white paper discusses the breadth of science that is possible with multimessenger observations of neutron star mergers. It then makes recommendations for the next decade, then beyond, to be sure we capture this science.
Burns,EricNASA GoddardOpportunities for Multimessenger Astronomy in the 2020s
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We present an overview of multimessenger science and the capabilities necessary to enable them. In short, we recommend a broad range of instruments and missions, with improved communication. We end with a table demonstrating this need.
Burns,EricNASA GoddardGamma Rays and Gravitational Waves
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The first multimessenger detection of a neutron star merger was independently detected in gamma-rays and gravitational waves. The two messengers will jointly identify new sources in the next few years, beyond neutron star mergers. We present a summary of possible sources and discuss the capabilities needed to study them.
Butler,BryanNational Radio Astronomy ObservatoryIndirect Detection of Extrasolar Planets via Radio Wavelength Astrometry
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Extrasolar giant planets in nearly face-on orbits are difficult to detect with transit or radial velocity techniques. They could be detected with a radio interferometer with sufficient resolution and sensitivity, via the wobble of the central star due to the orbiting planet. The next generation Very Large Array (ngVLA) is such an instrument.
Butterfield,NatalieGreen Bank ObservatoryInvestigating the gas in the Galactic Bar: the missing link between the Galactic Disc and the Central Molecular Zone
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This white paper highlights a scientific opportunity in the Galactic Bar. The bar is thought to mediate the flow of gas from the Disk towards the Center, fueling the extreme environment found within the inner region. Thus study of this region is critical for our understanding of the mass, energy and chemical evolution and transport across the Galaxy
Buzasi,DerekFlorida Gulf Coast UniversityFundamental Stellar Physics throughout the Galaxy
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Our understanding of stars is fundamental to our understanding of topics from circumstellar disks and exoplanets to the life history of galaxies, cosmological distance scales, and primordial nucleosynthesis. Spectroscopy and high-spatial resolution imaging can revolutionize open cluster studies by targeting the faintest stars in open clusters.
Caiazzo,IlariaUniversity of British ColumbiaTesting general relativity with accretion onto compact objects
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The X-ray emission of neutron stars and black holes presents a rich phenomenology that can help us answer: Does general relativity apply in the strong gravity regime? Are black holes described by the Kerr metric? We consider how to investigate these questions with a combination of high-spectral and high-timing resolution using TES arrays.
Caiazzo,IlariaUniversity of British ColumbiaHunting for ancient brown dwarfs: the developing field of brown dwarfs in globular clusters
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This white paper explores the expected advancements in the study of brown dwarfs in globular star clusters, thanks to the extraordinary sensitivity in the infrared of upcoming telescopes like JWST and the ELTs.
Caldwell,RobertDartmouth CollegeAstro2020 Science White Paper: Cosmology with a Space-Based Gravitational Wave Observatory
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The low frequency, mHz GW spectrum is a new frontier for cosmology. We present the cosmological questions that can be addressed from observations in this regime.
Calzetti,DanielaUniversity of Massachusetts, AmherstHow Do Stars Form? Open Questions on the Stellar Initial Mass Function
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This WP summarizes the recent progress on observations and models of short timescale star formation and the IMF. The challenges ahead include the relation between cores and stars, the physical nature of the characteristic mass, the existence and nature of a high-mass limit for stars, and the environment effects on stellar multiplicity and the IMF.
Campbell,BruceSmithsonian InstitutionRadar Astronomy for Planetary Surface Studies
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This paper addresses future use of ground-based radar facilities for studies of the surfaces of planets and satellites.
Capak,PeterCalifornia Institute of TechnologySynergizing Deep Field Programs Across Multiple Surveys
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A critical component of many past, present and future astronomical surveys is a dedicated deep field program. We argue these should be explicitly coordinated and considered in project design to maximize the scientific output of these important observations.
Caputo,ReginaNASA Goddard Space Flight CenterLooking Under a Better Lamppost: MeV-scale Dark Matter Candidates
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Two well-motivated dark matter candidates are weakly interacting massive particles (WIMPs) and weakly interacting sub-eV particles (WISPs) (e.g. axions). A new gamma-ray telescope that is optimized for MeV energies would allow us to explore new areas of dark matter parameter space and provide unprecedented access to its particle nature.
Carilli,ChristopherNRAOImaging molecular gas in high redshift galaxies at <=1 kpc resolution
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Imaging the cool molecular gas in distant galaxies, the fuel for star formation, at <= 1kpc resolution, is a prerequisite for future 'precision galaxy formation studies', addressing such basic issues as a Universal 'star formation law', cloud evolution and feed-back, and the dynamics and physical conditions in the cold gas in early galaxies.
Carilli,ChristopherNRAOResolving the Radio Photospheres of Main Sequence Stars
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We discuss the need for spatially resolved observations of the radio photospheres of main sequence stars. Such studies are fundamental to determining the structure of stars in the key transition region from the cooler optical photosphere to the hot chromosphere -- the regions powering exo-space weather phenomena.
Carpenter,KennethNASA's Goddard Space Flight CenterStars at High Spatial Resolution
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We summarize compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec angular resolution, UV/Optical spectral imaging observations. These can reveal details of many dynamic processes that affect stellar formation, structure, and evolution.
Cartwright,RichardSETI Institute / NASA Ames Research CenterExploring the composition of icy bodies at the fringes of the Solar System with next generation space telescopes
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This paper describes how next generation space telescopes can be used to investigate the compositions of ice giant satellites, icy dwarf planets, and mid-sized Trans-Neptunian Objects, over a wide range of wavelengths.
Casey,CaitlinUniversity of Texas at AustinTaking Census of Massive, Star-Forming Galaxies formed <1 Gyr After the Big Bang
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This concept paper focuses on strategies for finding and characterizing such early Universe (z > 3) dusty star-forming galaxies (DSFGs), with particular focus on pushing toward higher redshifts when DSFG formation scenarios place more stringent constraints on the formation of the earliest massive galaxies, <1 Gyr after the Big Bang.
Chang,Tzu-ChingJet Propulsion Laboratory, California Institute of TechnologyTomography of the Cosmic Dawn and Reionization Eras with Multiple Tracers
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We advocate a multi-tracer, large-scale approach to study the reionization and cosmic dawn eras. We highlight the line intensity mapping technique to trace the multi-phase reionization topology on large scales and reionization history in detail. We also advocate for Lya tomography mapping as an additional probe besides 21cm of the cosmic dawn era.
Chang,PhilipUniversity of Wisconsin - MilwaukeeCyberinfrastructure Requirements to Enhance Multi-messenger Astrophysics
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We outline the cyberinfrastructure requirements to enhance multi-messenger astrophysics and argue for a distributed cyberinfrastructure institute for multimessenger astrophysics to meet these challenges and take advantages of the associate opportunities.
Chanover,NancyNew Mexico State UniversityTriggered High-Priority Observations of Dynamic Solar System Phenomena
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Observations of unexpected dynamic phenomena will lead to important discoveries about solar system workings. We advocate for long-term/permanent programs on ground-based and space-based telescopes of all sizes -- including Extremely Large Telescopes (ELTs) -- to conduct observations of high-priority dynamic solar system phenomena.
Chartas,GeorgeCollege of CharlestonA New Era for X-ray Lensing Studies of Quasars and Galaxies
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Gravitational lensing can be used to infer the structure near black holes, constrain the dynamics and evolution of black-hole accretion and outflows, test general relativity and constrain the evolution of dark matter in galaxies. These science goals can be reached with a next generation sub-arcsec and high-throughput X-ray telescope.
Chary,Ranga RamIPAC/CaltechCosmology in the 2020s Needs Precision and Accuracy: The Case for Euclid/LSST/WFIRST Joint Survey Processing
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Cosmological breakthroughs in the 2020s will arise from measuring the redshift evolution of dark energy, resolving the tension in the expansion rate of the Universe, and understanding the impact of dark matter on galaxy substructure. Joint processing of Euclid/LSST/WFIRST data provides the most compelling, economical and tractable path forward.
Chaufray,Jean-YvesLATMOS/IPSL, CNRSUV Exploration of the solar system
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The UV spectral range is a crucial window to investigate a large area of phenomena for the objects of the solar system from the surface to the atmosphere and magnetosphere. In this white paper, we describe how future UV observations with high spectral resolution and polarimetric capability will bring new information on those subjects.
Checlair,JadeUniversity of ChicagoA Statistical Comparative Planetology Approach to Maximize the Scientific Return of Future Exoplanet Characterization Efforts
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We propose a statistical comparative planetology approach to test habitability hypotheses observationally. The key objective of this approach will be to make quick and cheap measurements of critical planetary characteristics on a large sample of exoplanets, exploiting statistical marginalization to answer broad habitability questions.
Chen,Hsiao-WenThe University of ChicagoTracking the Baryon Cycle in Emission and in Absorption
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This white paper describes the power of combining emission detections from wide-area integral field spectroscopy and absorption observations from echelle spectroscopy to enable the construction of spatially and spectrally resolved maps of gas flows in and out of galaxies and supermassive black holes across cosmic time.
Chen,ChristineSpace Telescope Science InstituteDebris Disk Composition: A Diagnostic Tool for Planet Formation and Migration
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Detailed studies of debris disk composition studies can address the scientific questions: (1) Are debris disk minor bodies similar to asteroids and comets in our Solar System? (2) Do planets separate circumstellar material into distinct reservoirs and/or mix material during planet migration?
Chen,BinNew Jersey Institute of TechnologyProbing Magnetic Reconnection in Solar Flares: New Perspectives from Radio Dynamic Imaging Spectroscopy
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Magnetic reconnection is a fundamental physical process in many laboratory, space, and astrophysical plasma contexts. In this white paper we emphasize the unique power of remote-sensing observations of solar flares at radio wavelengths in probing fundamental physical processes in magnetic reconnection.
Chluba,JensJodrell Bank Center for Astrophysics, University of ManchesterSpectral Distortions of the CMB as a Probe of Inflation, Recombination, Structure Formation and Particle Physics
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This WP describes the future science opportunities using CMB spectral distortions of the cosmic microwave background as a probe of fundamental physics.
Chomiuk,LauraMichigan State UniversityA Shocking Shift in Paradigm for Classical Novae
.pdf
The discovery of GeV gamma-rays from classical novae has led to a reassessment of these garden-variety explosions, and highlighted their importance for understanding radiative shocks, particle acceleration, and dust formation in more exotic, distant transients.
Chornock,RyanOhio UniversityMulti-Messenger Astronomy with Extremely Large Telescopes
.pdf
A key goal for Multi-Messenger Astronomy will be to characterize gravitational wave and neutrino sources using the next generation of Extremely Large Telescopes. These studies will have a broad impact across astrophysics. The counterparts to high-frequency GW sources will be distant and faint and thus demand ELT capabilities for characterization.
Christiansen,JessieCaltech/IPAC-NExScIMapping out the time-evolution of exoplanet processes
.pdf
In this white paper we identify predicted correlations, particularly trends in exoplanet populations, radii, orbits and atmospheres with host star age, that will allow us to begin identifying the dominant processes governing the formation and evolution of exoplanet systems.
Christiansen,JessieCaltech/IPAC-NExScIUnderstanding Exoplanet Atmospheres with UV Observations I: NUV and Blue/Optical
.pdf
In this white paper we focus on the science case for exoplanet observations at near-UV/blue optical wavelengths. Scattering information encoded in at these wavelengths can distinguish the cause of muted spectral features. These wavelengths also capture atmospheric escape processes, and help characterize mass loss from exoplanet atmospheres.
Churazov,EugeneMPAProbing 3D Density and Velocity Fields of ISM in Centers of Galaxies with Future X-Ray Observations
.pdf
Presence of large quantities of molecular gas in the vicinity of Sgr A* opens the possibility for synergetic studies of the supermassive black hole's past outbursts and the fundamental properties of the molecular clouds themselves. The full potential of this synergy can only be exploited with the next generation of X-ray observatories.
Ciardi,DavidCaltech/IPAC-NExScIToward Finding Earth 2.0: Masses and Orbits of Small Planets with Extreme Radial Velocity Precision
.pdf
Having discovered that Earth-sized planets are common, we are now embarking on a journey to determine if Earth-like planets are also common. To achieve this forward-looking goal, we must determine the masses and orbits of the planets; as such, the development of high quality precision radial velocity instruments and facilities is needed.
Cicone,ClaudiaINAF - Osservatorio Astronomico di BreraThe hidden circumgalactic medium
.pdf
The properties of the CGM are directly linked to the baryon cycle. Although traditionally the CGM should consist of warm/hot gas, recent breakthroughs suggest that a significant mass resides in a cold phase, which is filtered out by interferometers. The only way to probe such cold CGM is through a large (e.g. 50-m) single dish (sub-)mm telescope.
Ciprini,StefanoINFN Rome Tor Vergata and ASI Space Science Data Center ASI, Rome, ItalyGravitationally Lensed MeV Gamma-ray Blazars
.pdf
Gravitationally lensed gamma-ray blazars have large redshifts, huge BHs, powerful MeV photon-energy radiation. The pivotal MeV Universe is readyu for exploitation: lensed MeV blazars are rich multifreq./multimessenger laboratories (jet/central-engine spatial resolution, gamma rays/cosmic neutrinos/massive axions fluence enhancement and interference
Civano,FrancescaCenter for Astrophysics | Harvard & SmithsonianCosmic evolution of supermassive black holes: A view into the next two decades
.pdf
Discoveries over the past 20 years by Chandra and XMM-Newton surveys have significantly enhanced our view of supermassive black hole (SMBH) and galaxy evolution. We discuss new and exciting questions on the cosmic growth of SMBHs that can be addressed by new X-ray and multiwavelength observatories in the next two decades.
Clark,ChristopherSpace Telescope Science InstituteUnleashing the Potential of Dust Emission as a Window onto Galaxy Evolution
.pdf
We present the severe, systematic uncertainties currently facing our understanding of dust emission, which stymie our ability to truly exploit dust as a tool for studying galaxy evolution. We propose a program of study to tackle these uncertainties, describe the necessary facilities, and discuss the potential science gains that would result.
Clark,SusanInstitute for Advanced StudyMagnetic Fields and Polarization in the Diffuse Interstellar Medium
.pdf
Magnetism is one of the most important forces on interstellar gas dynamics, star formation, and Galactic evolution. The next decade will transform our understanding of interstellar magnetism if we invest in polarimetry: surveys of polarized dust emission, starlight polarization, and single-dish measurements of Zeeman splitting.
Clarke,JohnBoston UniversitySolar System Science with a Space-based UV Telescope
.pdf
Broad and scientifically critical observations of solar system bodies can be performed with either of the Astrophysics UV/visible telescopes currently under study (HabEx or LUVOIR). This white paper describes briefly a subset of the planetary science objectives that can only be met from above the atmosphere.
Cleeves,IlseUniversity of VirginiaRealizing the Unique Potential of ALMA to Probe the Gas Reservoir of Planet Formation
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ALMA has revolutionized our view of protoplanetary disks, revealing structures in dust emission likely sculpted by forming planets. Studying how gas assembles into planets and its broader chemical makeup requires higher spectral line sensitivity than currently possible. Accomplishing this science requires a major upgrade of ALMA in the 2030s era.
Colpi,MonicaUniversity of MilanThe Gravitational View of Massive Black Holes
.pdf
Gravitational wave observations will be game-changing for our understanding of massive black holes.
Colpi,MonicaUniversity of MilanThe Gravitational View of Massive Black Hole Mergers
.pdf
Note: this is to replace the earlier ColpiMonica.pdf submission, having forgotten to include several authors. Apologies.
Cooray,AsanthaUC IrvineCosmic Dawn and Reionization: Astrophysics in the Final Frontier
.pdf
The cosmic dawn and epoch of reionization mark the time period in the universe when stars, galaxies, and blackhole seeds first formed and the intergalactic medium changed from neutral to an ionized one. This white paper outlines the current state of knowledge, anticipated scientific outcomes in the 2020s and scientific goals for new facilities
Cordes,JamesCornell UniversityGravitational Waves, Extreme Astrophysics, and Fundamental Physics with Precision Pulsar Timing
.pdf
This white paper outlines a pulsar timing program that will provide precision masses of neutron stars, stringent tests of General Relativity, and the detectors for light-year wavelength gravitational wave astronomy and astrophysics: millisecond pulsars, nature's most precise clocks.
Cornish,NeilMontana State UniversityThe Discovery Potential of Space-Based Gravitational Wave Astronomy
.pdf
A space-based interferometer operating in the previously unexplored mHz gravitational band has tremendous discovery potential. If history is any guide, the opening of a new spectral band will lead to the discovery of entirely new sources and phenomena.
Corrales,LiaUniversity of MichiganAstromineralogy of interstellar dust with X-ray spectroscopy
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X-ray absorption fine structure (XAFS) in the 0.2-2 keV band is a crucial component in multi-wavelength studies of dust mineralogy, size, and shape. We discuss large open questions in astromineralogy and describe how planned and potential X-ray telescopes will play a key roll in answering those questions.
Corsi,AlessandraTexas Tech UniversityRadio Counterparts of Compact Object Mergers in the Era of Gravitational-Wave Astronomy
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GHz radio astronomy has played a fundamental role in the multi-messenger discovery of the binary neutron star merger GW170817. We show how the projected increase in sensitivity of gravitational-wave detectors over the next decade dramatically calls for an improvement in both sensitivity and spatial resolution on current U.S.-based radio arrays.
Cowperthwaite,PhilipCarnegie ObservatoriesJoint Gravitational Wave and Electromagnetic Astronomy with LIGO and LSST in the 2020's
.pdf
In this white paper, we outline the case for using some percentage of LSST survey time for dedicated target-of-opportunity follow up of GW triggers in order to efficiently and rapidly identify optical counterparts.
Creech-Eakman,MichelleNew Mexico Institue of Mining and TechnologyPulsation as a Laboratory for Understanding Stellar Physics
.pdf
This paper presents a review of stellar pulsation across the H-R diagram and the critical importance of pulsation investigations in order to make important inroads into understanding fundamental processes in stellar physics. This area of astrophysics has been largely overlooked by the community and is ripe for new discoveries over the next Decade.
Crichton,DanielJet Propulsion Laboratory, California Institute of TechnologyOn the Use of Planetary Science Data for Studying Extrasolar Planets
.pdf
There is an opportunity to advance solar system and extrasolar planetary studies that does not require new telescopes or new missions but better use and access to data sets. This approach leverages significant investment from space agencies in exploring the solar system and using those discoveries for the study of extrasolar planets.
Cristofari,PierreGran Sasso Science InstituteWhere are the pevatrons?
.pdf
The search for cosmic particle accelerators capable of reaching the PeV range, PeVatrons, is a crucial science target of the very-high-energy community. Such accelerators are essential in the context of the problem of the origin of Galactic cosmic rays, and in order to understand the mechanisms involved in the production of PeV particles.
Cuby,Jean-GabrielUniversity of Aix-MarseilleUnveiling Cosmic Dawn: the synergetic role of space and ground-based telescopes
.pdf
Euclid and WFIRST will find thousands of galaxies and quasars above redshift 7 during the epoch of reionization. Massive spectroscopic follow-up campaigns with existing and planned near-infrared and mm facilities will be required for confirmation and physical characterization. A properly coordinated large follow-up campaign is recommended.
Currie,ThayneNASA-Ames Research CenterThe Critical Strategic Importance of Adaptive Optics-Assisted Ground-Based Telescopes for the Success of Future NASA Exoplanet Direct Imaging Missions
.pdf
We describe how ground-based exoplanet direct imaging -- in the next decade with current telescopes and beyond with ELTs, through science programs and technological development -- is a key, strategic investment to help ensure the success of future NASA direct imaging missions (i.e. HabEx/LUVOIR).
Cutler,CurtJet Propulsion LaboratoryASTRO2020 DECADAL SCIENCE WHITE PAPER: WHAT WE CAN LEARN FROM MULTI-BAND OBSERVATIONS OF BLACK HOLE BINARIES
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We discuss some of the synergies that result when the same black hole (BH) binaries are observed both by space-based and ground-based gravitational-wave (GW) observatories. E.g., we show how combining such GW data sets can break degeneracies and so improve parameter estimation. We consider both stellar-mass and intermediate-mass BH binaries.
D'Urso,BrianMontana State UniversitySpace-Based Measurements of G
.pdf
The Newtonian Constant of Gravitation is among the most poorly measured fundamental constants in physics. We review recent measurements of G and propose a new space-based measurement of G in low earth orbit.
Dannerbauer,HelmutInstituto de Astrofísica de Canarias, Universidad de La LagunaMapping Galaxy Clusters in the Distant Universe
.pdf
We present the science case for mapping several thousand galaxy (proto)clusters at z=1-10 with a large aperture single dish sub-mm facility, producing a high-redshift counterpart to local large surveys of rich clusters like the well-studied Abell catalogue.
Darling,JeremyUniversity of ColoradoExtragalactic Proper Motions: Gravitational Waves and Cosmology
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We review the cosmological and local phenomena revealed by correlated extragalactic proper motions, their expected amplitudes, the current best measurements (if any), and predictions for Gaia. We describe key ground- and space-based observational requirements to measure or constrain these proper motion signals at the level of 100 nanoarcsec/year.
Darling,JeremyUniversity of ColoradoA Formaldehyde Deep Field
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A formaldehyde deep field (FDF) can provide a blind, mass-limited survey of molecular gas across the history of star formation and galaxy evolution. We present a fiducial FDF that would span redshifts z = 0–7 and use formaldehyde line ratios to measure the molecular hydrogen number density for z > 0.45.
Davidsson,BjornJet Propulsion Laboratory, California Institute of TechnologyDeciphering the Protostellar Disk Evolution Recorded by Cometary Deuterated Water
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We propose intensified efforts to determine the deuterium abundance in comet water for a large number of objects, and to use this information to better understand the physical and chemical evolution of protostars during their collapse phase.
De Beck,ElvireDepartment of Space, Earth and Environment, Chalmers University of TechnologyThe fundamentals of outflows from evolved stars
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Chemical evolution of the ISM and galaxies depends critically on stellar mass loss. We describe current efforts and future needs and opportunities to characterize AGB outflows: driving mechanisms, outflow rates, underlying fundamental physical and chemical processes such as dust grain formation, and dependency of these on metallicity.
de Kleer,KatherineCalifornia Institute of TechnologySolar System Satellites: Key Science Enabled by the ngVLA
.pdf
The solar system’s satellites include worlds with ongoing geological processes, complex atmospheric chemistry, and high astrobiological potential. Data at 1-100 GHz with high spatial resolution and sensitivity such as the ngVLA will provide would significantly advance our understanding of these bodies’ atmospheres and surface-interior exchange.
de Pater,ImkeUC BerkeleyPotential for Solar System Science with the ngVLA: the Giant Planets
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Radio wavelength observations of solar system bodies are a powerful method of probing the deep atmospheres of the giant planets, its rings, and magnetospheres. The ngVLA will enable the highest sensitivity and resolution observations of this kind, with the potential to revolutionize our understanding of these bodies.
De Zotti,GianfrancoINAF-Osservatorio Astronomico di PadovaEarly evolution of galaxies and of large-scale structure from CMB experiments
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Next generation CMB experiments with arcmin resolution will, for free, lay the foundations for a real breakthrough on the study of the early evolution of galaxies and galaxy clusters, thanks to the detection of large samples of strongly gravitationally lensed galaxies and of proto-clusters of dusty galaxies up to high redshifts.
De Zotti,GianfrancoINAF-Osservatorio Astronomico di PadovaRadio sources in next-generation CMB surveys
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Next-generation CMB experiments will provide samples of thousands radio sources allowing the investigation of the evolutionary properties of blazar populations, the study of the earliest and latest stages of radio activity, the discovery of rare phenomena and of new transient sources and events.
Debes,JohnSTScICold Debris Disks as Strategic Targets for the 2020s
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Cold debris disks (T<200 K) are analogues to the dust in the Solar System's Kuiper belt. We lay out a critical path for the study of debris disks that focuses on defining an empirical relationship between scattered light and thermal emission, probing the dynamics and properties of disks, and directly determining planet disk interactions.
DeMarines,JuliaUniversity of California, BerkeleyObserving the Earth as a Communicating Exoplanet
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This white paper highlights an observing project that aims to advance and refine our search for life in the Universe, measure the Earth’s technosignature over time, and foster collaborations between radio astronomers and the wider astrobiology community. This paper highlights the Moonbounce Project and opportunities for project expansion.
Dey,ArjunNational Optical Astronomy ObservatoryMass Spectroscopy of the Milky Way
.pdf
Massively multiplexed spectroscopic surveys of Milky Way stars will revolutionize our understanding of our Galaxy's structural components, revealing their past history and the small-scale structure of its dark matter halo. A spectroscopic survey of 10^8 stars, previously unimaginable, is now within reach of new instruments in the coming decade.
DI MAURO,MATTIANASA's Goddard Space Flight CenterProspects for the detection of synchrotron halos around middle-age pulsars
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Cosmic-ray positrons emitted by PWNe can produce photons, distributed in halos, at X-ray energies through synchrotron radiation. In this white paper we show that mission concepts, such as AMEGO AdEPT, are suitable to detect these synchrotron halos and we will report the list of the most promising PWNe that could be able to detect.
Dickinson,MarkNOAOObserving Galaxy Evolution in the Context of Large-Scale Structure
.pdf
Galaxies form and evolve in the context of their large-scale environments. Very large spectroscopic surveys (e.g., SDSS, GAMA) have been invaluable for quantifying this connection in the local universe. We consider advances in understanding galaxy evolution that would be enabled by very large, high-density spectroscopic surveys at high redshifts.
Do,TuanUCLAEnvisioning the next decade of Galactic Center science: a laboratory for the study of the physics and astrophysics of supermassive black holes
.pdf
We describe several research questions driving the next decade of Galactic center science: Is General Relativity (GR) the correct description for supermassive black holes? What is the nature of star formation in the GC? How do stars and compact objects dynamically interact with the SMBH? What physical processes drive gas accretion onto Sgr A*?
Doeleman,SheperdCenter for Astrophysics | Harvard and SmithsonianBlack Hole Physics on Horizon Scales
.pdf
High-resolution imaging of supermassive black holes can test general relativity and elucidate processes of accretion/jet formation on scales of the event horizon. Enhancements achievable within the decade would provide high-fidelity, time-resolved observations of Sgr A*, M87, and other black holes, enabling breakthroughs in black hole astrophysics.
Domagal-Goldman,ShawnNASA Goddard Space Flight CenterLife Beyond the Solar System: Remotely Detectable Biosignatures
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This white paper reviews the scientific community’s ability to use data from future telescopes to search for life on exoplanets. It summarizes products from the Exoplanet Biosignatures Workshop Without Walls (EBWWW). This effort led to papers that constituted the Exoplanet Analysis Group's (ExoPAG) 16th Science Assessment Group (SAG 16).
Dore,OlivierJPL/CaltechWFIRST: The Essential Cosmology Space Observatory for the Coming Decade
.pdf
Two decades after its discovery, cosmic acceleration remains the most profound mystery in cosmology. WFIRST emerged as a top priority of Astro2010 in part because of its ability to address the mystery of cosmic acceleration in powerful ways. Mission design changes since Astro2010 have made WFIRST an even more powerful dark energy facility.
Dragomir,DianaMITCharacterizing the Atmospheres of Irradiated Exoplanets at High Spectral Resolution
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We describe the potential of high-resolution cross-correlation spectroscopy on the Extremely Large Telescopes to 1) robustly measure atmospheric circulation and planetary rotation for hot Jupiters, and 2) measure atmospheric mass-loss and extract atmospheric composition information for sub-Neptunes, super-Earths and disintegrating planets.
Drake,JeremyCenter for Astrophysics | Harvard & SmithsonianHigh-Energy Photon and Particle Effects on Exoplanet Atmospheres and Habitability
.pdf
Energetic stellar photon and particle radiation evaporates and erodes planetary atmospheres and controls upper atmospheric chemistry. Understanding of exoplanet atmospheres, their evolution and determination of habitability requires a powerful high-resolution X-ray imaging and spectroscopic observatory to characterize stellar energetic radiation.
Dreier,CaseyThe Planetary SocietyThinking Big: How Large Aperture Space Telescopes Can Aid the Search for Life in Our Lifetimes
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We discuss the capabilities needed to conduct the most scientifically compelling endeavor currently facing space science: the successful search for life elsewhere. We provide the context for NASA’s search for life beyond the Earth, report our assessment of public support for this science, and ways for the Astro2020 process to address this goal.
Dressing,CourtneyUniversity of California, BerkeleyGround-Based Radial Velocity as Critical Support for Future NASA Earth-Finding Missions
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A precursor radial velocity (RV) survey would benefit direct imaging missions by (1) finding potentially habitable planets; (2) improving scheduling efficiency; (3) revealing massive planets that could be mistaken for Earth-mass planets; (4) providing the surface gravities necessary for interpreting atmospheric spectra and potential biosignatures.
Dupuy,TrentGemini Observatory, Northern OperationsEstablishing an Empirical Substellar Sequence to Planetary Masses
.pdf
Mass is the most fundamental parameter governing the life-history of all gaseous objects from stars to brown dwarfs and giant planets. Extending measurements of mass to the regime of directly imaged gas-giants, and spectroscopically characterizing this mass sample, will require the leap in angular resolution and sensitivity offered by the ELTs.
Dvorkin,CoraHarvard UniversityNeutrino Mass from Cosmology: Probing Physics Beyond the Standard Model
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This white paper focuses on different cosmological probes that can potentially be used to improve our constraints on the sum of neutrino masses in the upcoming decade.
Egami,EiichiSteward Observatory, University of ArizonaDetecting Metal-Free Forming Galaxies at High Redshift
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The next frontier in the study of high-redshift galaxies is the detection of the first-generation ``forming'' galaxies that are emerging out of metal-free gas clouds at the end of the cosmic dark ages. Here, we discuss the detectability of such metal-free forming galaxies at high redshift.
Eifler,TimUniversity of ArizonaPartnering space and ground observatories - Synergies in cosmology from LSST and WFIRST
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We recommend the exploration of joint survey strategies that combine the two top-ranked survey endeavors of the 2010 Decadal Survey, the ground-based Large Synoptic Survey Telescope (LSST) and the space-based Wide Field Infrared Survey Telescope (WFIRST). We detail several joint survey scenarios and quantify the information gain for cosmology.
Eikenberry,StephenUniversity of FloridaA Direct Measure of Cosmic Acceleration
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Two decades after the discovery of accelerating cosmic expansion, there remains no direct detection of a change in the expansion velocity versus time. Redshift drift directly determines H(z), thus it is arguably the cleanest measurement of expansion history. Dedicated experiments can detect redshift drift with a five-year observational baseline.
Emonts,BjornNational Radio Astronomy ObservatoryThe Radio Universe at Low Surface Brightness: Feedback & accretion in the circumgalactic medium
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The low-surface-brightness radio regime offers two novel science cases that will help understand the role of the high-z CGM in galaxy evolution: observing the cold molecular medium on scales of galaxy halos and tracing feedback through the Sunyaev-Zeldovich Effect onto the hot CGM. Compact mm interferometers will explore these new science fields.
Eracleous,MichaelThe Pennsylvania State UniversityAn Arena for Multi-Messenger Astrophysics: Inspiral and Tidal Disruption of White Dwarfs by Massive Black Holes
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Tidal disruptions of white dwarfs by intermediate-mass black holes can inform us of black hole demographics, stellar populations and dynamics in their vicinity, and the physics of accretion. We can harness the information with a combination of surveys surveys for electromagnetic observatories and low-frequency gravitational wave observations.
Erskine,DavidLawrence Livermore National LaboratoryDirect Acceleration: Cosmic and Exoplanet Synergies
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4 frontier science areas can make great strides with development of highly accurate and stable spectroscopy: • Cosmic redshift drift and direct detection of cosmic acceleration • Earth mass exoplanet detection from radial velocities • Milky Way structure mapping through stellar accelerations • Dark matter properties thru Milky Way gravity mapping
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics: The Exploration Question for Resolved Stellar Populations
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. Here we focus on exploration of resolved stellar populations
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics The Exploration Question for Stars and Stellar Evolution
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. Here we focus on exploration for stars and stellar evolution
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics The Exploration Question for Planetary Systems
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. Here we focus on exploration for planetary systems.
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics The Exploration Question for Galaxy Evolution
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. Here we focus on exploration for galaxy evolution.
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics The Exploration Question for Cosmology
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. Here we focus on exploration for cosmology.
Fabbiano,GiuseppinaCenter for Astrophysics | Harvard & SmithsonianIncreasing the Discovery Space in Astrophysics The Exploration Question for Compact Objects
.pdf
Exploration can be the central question for Astro2020. Major astronomical discoveries were not driven by known questions, but by increasing discovery space via new telescopes and instruments, & now archive mining. Revolutionary facilities and supporting archives will open new discoveries. We focus on compact objects & multi-messenger exploration.
Faherty,JacquelineAmerican Museum of Natural HistoryBrown Dwarfs and Directly Imaged Exoplanets in Young Associations
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In this white paper we summarize the opportunity for discovery space in the coming decade of isolated brown dwarfs with planetary masses in young stellar associations within 150 pc. We suggest that next generation telescopes need to invest in characterizing young brown dwarfs in order to fully understand the atmospheres of sibling exoplanets.
Fan,XiaohuiUniversity of ArizonaThe First Luminous Quasars and Their Host Galaxies
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High-Redshift quasars probe the growth of early supermassive black holes (SMBHs) in the universe. In the next decade, new observations will push the frontier to the first luminous quasars at z>9, probe fainter quasar populations that trace earlier phases of BH growth, and connect SMBH growth with the rise of the earliest massive galaxies.
Ferraro,SimoneLawrence Berkeley National LaboratoryInflation and Dark Energy from spectroscopy at z > 2
.pdf
Multi-Object Spectroscopy at 2 < z < 5 can greatly improve our understanding of Inflation, Dark Energy and neutrino masses, while relaxing some restrictive modeling assumptions.
Fields,BrianUniversity of IllinoisNear-Earth Supernova Explosions: Evidence, Implications, and Opportunities
.pdf
Geological and lunar evidence of radioactive 60Fe implies that at least one supernova exploded within 100 pc of Earth within the last few Myr. The unique information provided by 60Fe to assess nearby supernovae make now a compelling time for the astronomy community to advocate for supporting multi-disciplinary, cross-cutting research programs.
Finkelstein,StevenThe University of Texas at AustinUnveiling the Phase Transition of the Universe During the Reionization Epoch with Lyman-alpha
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The observation of Lyman-alpha emission from galaxies in the epoch of reionization (6 < z < 10) provides the best opportunity to obtain a detailed measurement of the temporal and spatial evolution of this phase change in the next decade. These observations require large (>20m) collecting areas to reach attenuated emission from faint galaxies.
Fischer,WilliamSpace Telescope Science InstituteTime-Domain Photometry of Protostars at Far-Infrared and Submillimeter Wavelengths
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The majority of the main-sequence mass of a star is assembled in the protostellar phase, where a forming star is embedded in an infalling envelope and encircled by a protoplanetary disk. We discuss the progress that would be enabled with far-infrared and submillimeter programs to probe protostellar accretion variability in the nearest kiloparsec.
Fissel,LauraNRAOStudying Magnetic Fields in Star Formation and the Turbulent Interstellar Medium
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Future developments in instrument sensitivity for ground-based, airborne, and space-borne polarimeters operating over range of spatial scales are critical for enabling revolutionary steps forward in our understanding of the magnetized turbulence from which stars are formed.
Flagey,NicolasCanada-France-Hawaii Telescope CorporationProbing the Interstellar Medium in the 2020s and Beyond
.pdf
We describe how a dedicated facility with a wide field of view, large aperture, highly multiplexed, multi-object, high resolution spectrograph will unify our understanding of the gas structure in galaxies by placing measurements of interstellar absorption features used to trace diffuse gas on an equal footing with those of H I and CO emission.
Fleischhack,HenrikeMichigan Technological UniversityPulsars in a Bubble? Following Electron Diffusion in the Galaxy with TeV Gamma Rays
.pdf
TeV Halos, extended regions of gamma-ray emission around pulsars, are a new class of gamma-ray sources. They can be used to study pulsar properties and e+e- diffusion on scales of ~10 pc, as well as to find misaligned pulsars. We outline the contributions of future gamma-ray instruments to the study of TeV Halos and the expected physics outcomes.
Fleishman,GregoryNew Jersey Institute of TechnologySolar Coronal Magnetic Fields: Quantitative Measurements at Radio Wavelengths
.pdf
Quantitative measurements of coronal and chromospheric magnetic field is currently in its infancy. We describe a foundation of such observations , which is a key input for MHD numerical models of the solar atmosphere and eruptive processes, and a key link between lower layers of the solar atmosphere and the heliosphere.
Foley,RyanUC Santa CruzGravity and Light: Combining Gravitational Wave and Electromagnetic Observations in the 2020s
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Within ten years, we will detect hundreds of GW events. We will explore exotic astrophysical topics ranging from nucleosynthesis, stellar evolution, general relativity, high-energy astrophysics, nuclear matter, to cosmology. We outline some of the most exciting scientific questions that can be answered by combining GW and EM observations.
Foley,RyanUC Santa CruzWFIRST: Enhancing Transient Science and Multi-Messenger Astronomy
.pdf
Ground-based observatories will discover thousands of transients in the optical, but will not provide the NIR photometry and high-resolution imaging of a space-based observatory. WFIRST can fill this gap. With its SN Ia survey, WFIRST will also discover thousands of other transients in the NIR, revealing the physics for these high-energy events.
Fonseca,EmmanuelMcGill UniversityFundamental Physics with Radio Millisecond Pulsars
.pdf
We summarize the state of the art and future directions in using millisecond radio pulsars to test gravitation and measure intrinsic, fundamental parameters of neutron stars.
Ford,K. E. SaavikCUNY BMCC/Am. Museum of Natural History/CUNY GCAGN (and other) astrophysics with Gravitational Wave Events
.pdf
LIGO-detected stellar mass binary black hole (sBBH) mergers may be used to constrain key parameters of AGN disks. This is true even if AGN are not primarily responsible for driving sBBH mergers. We outline how to organize GW, EM, and neutrino observations to gather maximal astrophysical information on important drivers of galactic evolution.
Ford,EricThe Pennsylvania State UniversityAdvanced Statistical Modeling of Ground-Based RV Surveys as Critical Support for Future NASA Earth-Finding Missions
.pdf
Realizing the potential of the upcoming generation of Doppler exoplanet surveys will require considerable investment in advanced stellar modeling, statistical and machine-learning methodologies, and Doppler pipelines.
Ford,EricThe Pennsylvania State UniversityCharacterizing Exoplanet Populations as a Constraint on Planet Formation and Input for Future NASA Missions
.pdf
The scientific impact of future exoplanet discoveries can be amplified if they are part of survey that have been designed and characterized to enable statistically valid characterization of exoplanet populations. As an example, we show recent characterization of exoplanet occurrence rates based on Kepler and Gaia data products.
Fortney,JonathanUniversity of California, Santa CruzThe Need for Laboratory Measurements and Ab Initio Studies to Aid Understanding of Exoplanetary Atmospheres
.pdf
We are now in the new era of the characterization of exoplanet atmospheres. However, atmosphere models are often limited by insufficiencies in the laboratory and theoretical data that serve as critical inputs. Here we provide descriptions of areas where new investigations could fill critical gaps in our ability to model exoplanet atmospheres.
Fossati,LucaSpace Research Institute, Austrian Academy of SciencesUltraviolet Spectropolarimetry as a Tool for Understanding the Diversity of Exoplanetary Atmospheres
.pdf
We show that a high-resolution spectropolarimeter with a broad wavelength coverage, particularly if attached to a large space telescope, would enable simultaneous study of the polarimetric exoplanet properties of the continuum and to look for and characterize the polarimetric signal due to scattering from single molecules.
Fox,AndrewSpace Telescope Science InstituteThe Magellanic Stream as a Probe of Astrophysics
.pdf
The Magellanic Stream is the most spectacular example of a gaseous stream in the local Universe. In this white paper, we emphasize the Stream’s importance for many areas of Galactic astronomy, summarize key unanswered questions, and identify future observations and simulations needed to resolve them.
Fox,AndrewSpace Telescope Science InstituteSpectroscopic Observations of the Fermi Bubbles
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The Fermi Bubbles are two giant plasma lobes extending 10 kpc above and below the Galactic Center. Here we identify the scientific themes that have emerged from spectroscopic studies of the Bubbles, determine key open questions, and describe the observations needed in the next decade to characterize the nuclear wind and its impact on the Galaxy.
Fraija,NissimInstituto de Astronomia, UNAM, Mexico53 of 150
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In this paper, we review the importance to have a wide field-of-view TeV gamma-ray observatory with a large duty cycle in order to study Active Galactic Nuclei (AGN) phenomena at very-high energies (photons with energies larger than 100 GeV). We focus in blazars, a special sub-class of AGN.
Fraija,NissimInstituto de Astronomia, UNAM, Mexico41 out of 150
.pdf
In this paper, we review the importance to have a wide field-of-view TeV gamma-ray observatory with a large duty cycle in order to study cosmic rays in the energy range of TeV – PeV.
France,KevinUniversity of ColoradoDetecting Protoplanets and Tracing the Composition and Evolution of Planet-forming Material with Large UV/Optical Observatories
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This white paper describes how future, large (primary apertures larger than ~12m) UV/optical observatories can detect accreting protoplanets, quantify the evolution of material at planet-forming radii, and provide new constraints on the dispersal of material through disk winds.
Frank,AdamUniversity of RochesterExoplanets and High Energy Density Plasma Science
.pdf
In this white paper we review the state of exoplanet interior studies and the ability of High Energy Density Plasma (HEDP) WDM techniques to address critical open issues.
Friesen,RachelNational Radio Astronomy ObservatoryStar-Forming Filaments and Cores in Molecular Clouds
.pdf
Dense, star-forming gas in molecular clouds is dominated by filamentary structures. We describe the best probes of the dynamics of filaments and cores in nearby star-forming molecular clouds, and our recommendations for furthering our understanding of star formation physics through observations over the next decade.
Fryer,ChrisLos Alamos National LaboratoryCore-Collapse Supernovae and Multi-Messenger Astronomy
.pdf
Multi-messenger diagnostics for core-collapse supernovae span a wide range of diagnostics including observations across the entire electromagnetic spectrum, neutrinos, cosmic rays, dust grains and, in the future, gravitational waves. With next generation detectors, these multimessenger signals will probe all aspects of these energetic phenomena.
Fundator,MichaelRutgers UniversityGalileo Galilei versus Aristotle, Philosophy of motion, Galileo’s contemporaries, very large numbers, Fermat’s Last Theorem, and speed of light.
.pdf
Galileo’s opposition to Aristotle’s concepts of motion developed into square dependence in the philosophical thought on kinematics and dynamics, Galileo’s transformation and concepts including infinite, theory of motion, analytical geometry, measurement of speeds of light and sound, theory of numbers with focus on very large numbers.
Fundator,MichaelRutgers UniversityApplication of timescale, magnitudes, and fractal time with Stein estimators to astronomical observations.
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Discussion of spatial time multiscale multidimensional and multifractal time analysis with different magnitudes through examples in Number and Algebraic theories and Tidal Theory turbulence applied to astronomical observations and Galaxy suggests Stein type estimators to more accurate orbits evaluation with notice by Poincare on Kepler.
Fundator,MichaelRutgers UniversityTheory of motion with historical perspective.
.pdf
Discussion of the theory of motion from Aristotle to Newton
Furlanetto,StevenUniversity of California Los AngelesSynergies Between Galaxy Surveys and Reionization Measurements
.pdf
The epoch of reionization is one of the most exciting frontiers in astrophysics. Here we describe how the combination of galaxy surveys and direct 21-cm measurements of reionization can illuminate numerous mysteries of this fascinating era.
Furlanetto,StevenUniversity of California Los AngelesInsights Into the Epoch of Reionization with the Highly-Redshifted 21-cm Line
.pdf
We describe how direct measurements of the reionization process with the 21-cm line of neutral hydrogen will enable science investigations of that era.
Furlanetto,StevenUniversity of California Los AngelesFundamental Cosmology in the Dark Ages with 21-cm Line Fluctuations
.pdf
We describe how 21-cm measurements of the "Dark Ages," between cosmological recombination and the formation of the first luminous sources, can enable new tests of cosmology.
Gaensicke,BorisUniversity of WarwickEvolved Planetary Systems around White Dwarfs
.pdf
This white paper describes an ambitious research programme into the architectures of evolved planetary systems and their use as probes of the bulk abundances of exo-planetesimals, and we identify the facilities required over the next decade to reach our scientific goals.
Gallo,ElenaUniversity of MichiganTowards a high accuracy measurement of the local black hole occupation fraction in low mass galaxies
.pdf
This document illustrates the feasibility of a few per cent level measurement of the local black hole occupation fraction in low mass galaxies through wide-field, high angular resolution X-ray imaging observations of local volume galaxies.
Garcia,JavierCalifornia Institute of TechnologyProbing the Black Hole Engine with Measurements of the Relativistic X-ray Reflection Component
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We discuss the observational and theoretical challenges expected in the exploration, discovery, and study of astrophysical black holes in the next decade. We focus on the case of accreting black holes and their electromagnetic signatures, with particular emphasis on the measurement of the relativistic reflection component in their X-ray spectra.
Garcia,MiriamCentro de Astrobiologia, CSIC-INTAWalking along Cosmic History: Metal-poor Massive Stars
.pdf
This paper proposes to supersede the SMC standard with a new metallicity ladder built from very metal-poor galaxies, and provides a brief overview of the technological facilities needed to this aim.
Gary,DaleNew Jersey Institute of TechnologyParticle Acceleration and Transport, New Perspectives from Radio, X-ray, and Gamma-Ray Observations
.pdf
Particle acceleration and particle transport are ubiquitous in astrophysics. The Sun offers an astrophysical laboratory to study these in minute detail, using radio dynamic imaging spectroscopy to measure coronal magnetic fields, time and space evolution of the electron distribution function.
Gaspar,AndrasSteward Observatory, The University of ArizonaModeling Debris Disk Evolution
.pdf
Understanding the formation, evolution, and architectures of planetary systems requires detailed knowledge of their components. Debris disks provide a means with which we can study them. The next decade will deliver a wealth of new information on the nearest systems. Parallel advances in modeling will be necessary to interpret these new datasets.
Gaudi,B. ScottThe Ohio State University‘Auxiliary’ Science with the WFIRST Microlensing Survey
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The WFIRST Microlensing Survey will enable the measurement of the compact object mass function over ten orders of magnitude, the detection of ~100,000 Transiting Planets, astroseismology of ~1,000,000 bulge giants, the detection of ~5000 trans-Neptunian objects, and measurement of parallaxes and proper motions of ~6,000,000 bulge and disk stars.
Geach,JamesUniversity of HertfordshireThe case for a 'sub-millimeter SDSS': a 3D map of galaxy evolution to z~10
.pdf
We argue that a 'sub-millimeter SDSS' - a sensitive large-area imaging+spectroscopic survey in the sub-mm window - will revolutionize our understanding of galaxy evolution in the early Universe.
Gelfand,JosephNYU Abu DhabiMeV Emission from Pulsar Wind Nebulae: Understanding Extreme Particle Acceleration in Highly Relativistic Outflows
.pdf
There is considerable observation evidence that electrons and positions inside pulsar wind nebula are accelerated to at least PeV energies. However, how and to what energies particles are accelerated in these sources is poorly understood. Answering these questions requires measuring the MeV emission from these sources.
Ghosh,TapasiGreen Bank Observatory, WVRadio Spectral Line Probe of Evolution of Fundamental Constants
.pdf
Comparisons between the redshifts of multiple spectral transitions from distant galaxies provide a sensitive probe of evolution in fundamental constants such as the fine structure constant and the proton-electron mass ratio over cosmological epochs. Here, we the summarize the current status & the directions for progress with large radio telescopes.
Gies,DouglasGeorgia State UniversityHigh Angular Resolution Astrophysics: Evolutionary Impact of Stellar Mass Loss
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This is a discussion of how high angular resolution investigations will explore the processes of mass ejection at unprecedented photospheric scales.
Gilbert,KarolineSpace Telescope Science InstituteConstruction of an L∗ Galaxy: the Transformative Power of Wide Fields for Revealing the Past, Present and Future of the Great Andromeda System
.pdf
Our understanding of the M31 system will be transformed in the 2020s with wide field facilities for photometry (HST-like sensitivity and resolution) and spectroscopy (10 m class telescope, > 1 deg2 field, highly multiplexed, R ∼ 3000 – 6000). We focus on the power of these facilities to constrain the past, present, and future merger history of M31.
Ginsburg,AdamNational Radio Astronomy ObservatoryGalactic center star formation & feedback: key questions
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The closest galaxy center is a powerful laboratory for studying the secular processes that shape galaxies across cosmic time. Large-scale, high-resolution studies of this section of the Galaxy will connect Galactic star formation studies to extragalactic.
Gluscevic,VeraUniversity of FloridaCosmological Probes of Dark Matter Interactions: The Next Decade
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We discuss observational and theoretical advancements that will play pivotal roles in realizing a strong program of cosmological searches for the fundamental nature of dark matter in the coming decade. We focus on next-generation measurements of the CMB anisotropy and spectral distortions, Ly-alpha forest, galaxies, and cosmological 21-cm signals.
Goicoechea,Javier R.CSIC, Madrid, SpainStellar Feedback in the ISM Revealed by Wide-Field Far-Infrared Spectral-Imaging
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Atomic and molecular far-IR ( ~30 to 350 microns) lines are the most sensitive probes of stellar feedback processes. They allow us to quantify the deposition and cycling of energy in the ISM. In this white paper we emphasize the need of a space telescope with wide-field spectral-imaging capabilities in the critical far-IR domain.
Gordon,KarlSpace Telescope Science InstituteInterstellar Dust Grains: Ultraviolet and Mid-IR Extinction Curves
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Interstellar dust extinction curves in the UV and MIR to probe the 2175 A bump (carbonaceous), 3.4 micron (carbonaceous), and 10/20 micron features (silicates) as one of the main pillars of our understand of dust grains. Need capabilities to obtain large samples of UV and NIR spectra of ISM sightlines throughout the Local Group.
Graham,MelissaUniversity of WashingtonDiscovery Frontiers of Explosive Transients: An ELT and LSST Perspective
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We present several examples of future scientific impacts in the field of explosive transient astrophysics that will be generated by the combination of discoveries with the Large Synoptic Survey Telescope and follow-up with the Extremely Large Telescopes, and discuss practical aspects such as data infrastructures required to enable LSST+ELT synergy.
Green,DanielUniversity of California San DiegoMessengers from the Early Universe: Cosmic Neutrinos and Other Light Relics
.pdf
Measurements of the radiation density of the universe offer a broad window into both cosmic history and particle physics. Future cosmological observations, in particular of the cosmic microwave background, could reach clear observational targets that would lead to insights into nature and our universe that cannot be obtained by any other means.
Green,JoelSpace Telescope Science InstituteVariability in the Assembly of Protostellar Systems
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The impact of variability on protostellar systems due to accretion bursts is largely unknown. High (spectral resolution capabilities with rapid response times in the IR, X-ray, and radio are critical to follow the course of accretion and outflow during a protostellar outburst. This is not covered by currently existing or approved instrumentation.
Greene,ThomasNASA Ames Research CenterCharacterizing Transiting Exoplanets with JWST Guaranteed Time and ERS Observations
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We highlight how guaranteed time observations and early release science will advance understanding of exoplanet atmospheres and provide a glimpse into what transiting exoplanet science will be done with JWST during its first year of operations. JWST will be the most important mission for characterizing exoplanet atmospheres in the 2020s.
Greene,JennyPrinceton UniversityThe Local Relics of of Supermassive Black Hole Seeds
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In the coming decade we will have the capability to dynamically detect 1000 to hundred thousand solar mass black holes should they exit. This white paper describes how measuring the mass function of the elusive intermediate-mass black holes will provide unique insight into the formation of the first massive black holes.
Grin,DanielHaverford CollegeGravitational probes of ultra-light axions
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We summarize the high-energy theoretical and astrophysical motivation for ultra-light axions. We summarize observational signatures and possibilities for the next decade, and make recommendations for future theoretical and observational work.
Grindlay,JonathanHarvard UniversityBig Science with a nUV-MidIR Rapid-Response 1.3m Telescope at L2
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Fundamental Questions in Astrophysics can be addressed by a space telescope designed for rapid-response broad band imaging and spectroscopy. A brief description of the Time-domain Spectroscopic Observatory, a Probe-Class mission for L2, is given.
Grohs,EvanUniversity of California, BerkeleyBig Bang Nucleosynthesis and Neutrino Cosmology
.pdf
White paper on the theoretical, computational, observational, and experimental aspects of big bang nucleosynthesis.
Grossan,BruceUC Berkeley Space Sciences LaboratoryMeasurement of the Optical-IR Spectral Shape of Prompt Gamma-Ray Burst Emission: A Timely Call to Action for Gamma-Ray Burst Science
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Gamma-ray burst (GRB) spectra appear the same in gamma bands for different emission mechanisms. The optical-IR (OIR) spectra are different, however, allowing a clear test of synchrotron mechanisms. We argue that multi-channel OIR instruments should therefore be added to GRB-capable missions to do this important, undervalued science.
Gry,CecileLaboratoire d'Astrophysique de Marseille, Aix Marseille Univ.Far- to near-UV spectroscopy of the interstellar medium at very high resolution and very high signal-to-noise ratio
.pdf
A comprehensive study of the ISM phases and the nature of their connections requires comparing abundances and velocity profiles of tracers of the different phases. A wealth of absorption features from such tracers are found in the full UV domain that need to be observed at high resolving power R>200 000 and high signal-to-noise ratio SNR>500.
Gudipati,MurthyJet Propulsion Laboratory, California Institute of TechnologyFrom Interstellar Ice Grains to Evolved Planetary Systems: The Role of Laboratory Studies
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Laboratory studies that are directed towards understanding how simple astrophysical molecules evolve and how complex molecules are produced, preserved, and transported from interstellar conditions through the protoplanetary phase to an evolved planetary system. We emphasize the status of current laboratory research and future needs.
Guiriec,SylvainGeorge Washington University / NASA Goddard Space Flight CenterGamma-Ray Science in the 2020s
.pdf
With very large fields of view, high-cadence sampling, high angular, and spectral resolutions, and polarization capabilities, the new generation gamma-ray instruments are ready to address the most pressing science questions of the next decades, and they are essential for the time-domain multi-messenger era.
Gultekin,KayhanUniversity of MichiganBlack Holes Across Cosmic Time
.pdf
In the coming decade, 30-m class telescopes will allow us to make dynamical mass measurements of the largest black holes (1) in the local universe, which is critical for understanding the black hole mass function, and (2) out to z~1.5, which is critical for black hole growth and charting the coevolution (or not) of black holes and galaxies.
Gutermuth,RobertUniversity of Massachusetts AmherstDense Cores, Stellar Feedback and the Origins of Clustered Star Formation
.pdf
The study of dense gas cores is primed to bring valuable new insight into the star-formation process in the coming decade by leveraging growing capabilities in observations, simulations, and physical analysis.
Günther,Hans M.MITThe fastest components in stellar jets
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Outflows and jets are a crucial component of the star formation process. The innermost components of those jets are launched close to the star and thus probe the connection between star, disk, and magnetic field. Observations with high spatial resolution in the UV and X-rays are required to probe these fast winds.
Hagen,LeaSTScISpatially Resolved Observations of the Ultraviolet Attenuation Curve
.pdf
UV attenuation curves are used to correct rest-frame UV galaxy fluxes, and they encode information about dust-star geometry and dust grain properties. Spatially resolved measurements of the UV attenuation curve in the local universe will enable better constraints on corrections, dust geometry, and dust grains across all redshifts.
Haiman,ZoltanColumbia UniversityElectromagnetic Window into the Dawn of Black Holes
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The origin of massive black holes in the early universe is one of the major puzzles in astrophysics. Future X-ray surveys can detect BHs with mass M<10^5 Msun at z>10, and OIR observations can characterize their immediate environment. These observations will open a window into the "Dawn of Black Holes" and distinguish models of their origin.
Hammel,HeidiAURASolar System Science with the James Webb Space Telescope
.pdf
NASA’s space telescopes advance Solar System exploration in ways that complement in situ planetary spacecraft. As an example, we review some of the Solar System science planned for the James Webb Space Telescope. We envision similar robust planetary science cases for other future astrophysics flagships, particularly LUVOIR.
Haqq-Misra,JacobBlue Marble Space Institute of ScienceSearching for Technosignatures: Implications of Detection and Non-Detection
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The search for technosignatures from the Galaxy or the nearby universe raises two main questions: What are the possible characteristics of technosignatures? and How can future searches be optimized to enhance the probability of detection? Addressing these questions requires an interdisciplinary approach, which is described in this white paper.
Harding,J. PatrickLos Alamos National LaboratoryExploring Beyond-the-Standard-Model Physics with TeV Gamma-rays
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We consider three well-motivated beyond-the-Standard-Model searches for which the next generation of high-energy observatories will be well-suited: dark matter in the forms of primordial black holes and axion-like particles and violations of Lorentz invariance.
HARDING,AliceNASA Goddard Space Flight CenterProspects for Pulsar Studies at MeV Energies
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Enabled by the Fermi Large Area Telescope, we now know that pulsars fill the gamma-ray sky, and we are beginning to understand their emission mechanism and their distribution throughout the Galaxy. To address key questions calls for a sensitive, wide-field MeV telescope, which can detect the population of MeV-peaked pulsars hinted at by Fermi.
Harman,ChesterColumbia UniversityA Balancing Act: Biosignature and Anti-Biosignature Studies in the Next Decade and Beyond
.pdf
This white paper elaborates on the need for a quantitative biosignature identification and assessment framework to produce a numerical estimate for the likelihood that a given world has life. This will provide a comprehensive means to weigh planetary habitability alongside potential biosignatures and their respective false positives.
Harrington,KevinArgelander Institute for Astronomy, Bonn, GermanyThe Extended Cool Gas Reservoirs Within z > 1 (Proto-)Cluster Environments
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This work focuses on the major role large radio/millimeter (mm) single dish facilities will have in constraining the bulk, cold molecular and atomic gas content. We calculate how the high-sensitivity of the GBT's unblocked 100m aperture provides vital interferometric short-spacing coverage to support higher-resolution ngVLA observations.
Heap,SaraEmerita scientist, Goddard Space Flight CenterUnderstanding Cosmic Evolution: The Role of UV Spectroscopic and Imaging Surveys
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A Probe-class ultraviolet (UV) telescope having capabilities not available to Hubble can help answer many outstanding Key Science Questions posed by Astro2010. Measurements of the processed UV data will increase the scientific yield and impact of this telescope.
heiles,carluniversity of california at berkeleyGalactic and Extragalactic Astrochemisry: Heavy-Molecule Precursors to Life?
.pdf
Dense interstellar clouds contain an astonishingly rich collection of exotic molecules in various states of ionization and excitation, revealing complex astrochemistry. Charged molecules may moderate the magnetic field during star formation. The largest ones, which may be precursors to life, are best identified at 0.5-10 GHz with big telescopes.
Hensley,BrandonPrinceton UniversityDetermining the Composition of Interstellar Dust with Far-Infrared Polarimetry
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Does interstellar dust come in distinct silicate and carbonaceous varieties, or are interstellar grains a homogeneous mishmash of different materials? We argue that sensitive dust polarimetry from ~100-850um can provide a definitive test, with implications ranging from the evolution of metals in the ISM to component separation in CMB experiments.
Heyer,MarkUniversity of Massachusetts, AmherstFar Infrared Spectroscopic Imaging of the Neutral Interstellar Medium in Galaxies
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We describe the importance of obtaining velocity-resolved far-infrared emission lines to investigate the thermodynamics of the neutral ISM, the assembly of giant molecular clouds, interstellar turbulence, and radiative feedback.
Heyl,JeremyUniversity of British ColumbiaExploring the physics of neutron stars with high-resolution, high-throughput X-ray spectroscopy
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Combining TES detectors with collector optics will also us to study neutron stars in much greater detail by achieving high-energy resolution (1 eV) with much larger collecting areas to uncover even weak spectral features over a wide range of the photon energies. Perhaps we will finally be able to study neutron stars like stars.
Hickox,RyanDartmouth CollegeResolving the cosmic X-ray background with a next-generation high-energy X-ray observatory
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We review progress in understanding the high-energy X-ray emission from active galactic nuclei, and highlight exciting opportunities for a future high-resolution, hard (1-200 keV) X-ray observatory to resolve the cosmic X-ray background and characterize accreting supermassive black holes across cosmic time.
hillenbrand,lynnecalifornia institute of technology / astronomyYoung Pre-Main Sequence Stars: Accretion/Outflow, Planet Formation, and Contraction/Spin-Up on the Active Journey to a Main Sequence Life of Boredom
.pdf
The field of star formation, young stellar objects, and pre-main sequence stars has benefitted from the combined set of wide-field, multi-wavelength photometric surveys over the past two decades. What is currently lacking is a comparable effort in spectroscopy. This position paper makes the case that major spectroscopic investments are needed.
Hinkel,NatalieSouthwest Research InstituteStellar Characterization Necessary to Define Holistic Planetary Habitability
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It is a truism that “to know the planet, you must know the star.” We discuss important stellar characteristics that require attention in upcoming ground- and space-based missions, such that their processes can be either detangled from that of the planet, correlated with the presence of a planet, or utilized in lieu of direct planetary observations.
Hinkel,NatalieSouthwest Research InstituteAn Interdisciplinary Perspective on Elements in Astrobiology: From Stars to Planets to Life
.pdf
Stellar elemental abundances directly impact planetary interiors, surface composition, and life. However, communities necessary for habitability (astrophysics, planetary science, geology, biology) emphasize different elements. We must broaden our communication regarding lists of useful elements and how they can be observed in the near and long term
Hložek,RenéeDepartment of Astronomy and Astrophysics & Dunlap Institute for Astronomy and Astrophysics, University of TorontoSingle-object Imaging and Spectroscopy to Enhance Dark Energy Science from LSST
.pdf
This white paper describes the science opportunities to greatly improve measurements of cosmological parameters from LSST made possible by community access to single-object imaging and spectroscopy on telescopes with apertures ranging from 4-40m. Companion papers discuss opportunities from both deep and wide-field multi-object spectroscopy.
Hodges-Kluck,EdmundUniversity of Maryland/NASA GSFCHow does dust escape from galaxies?
.pdf
A large fraction of all the dust ever produced resides outside of the galaxies in which it was formed. Studies in the past decade broadly characterized the circumgalactic dust, but a study of outflowing or stripped dust around individual galaxies is needed to understand how it escapes. We discuss the prospects and requirements to do this.
Hodges-Kluck,EdmundUniversity of Maryland/NASA GSFCHot Drivers of Stellar Feedback from 10 to 10,000 pc
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Stellar feedback begins in individual star clusters but shapes entire galaxies. It operates in large part through work done by hot gas, but observational constraints on the nature of this gas remain poor on all scales, leading to major uncertainties in galaxy evolution models. We explore how new X-ray observations can make breakthrough progress.
Hogan,JasonStanford UniversityGravitational Waves in the Mid-band with Atom Interferometry
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We discuss the science possibilities for gravitational wave astronomy in the mid-band frequency range (30 mHz to 10 Hz) in the context of the MAGIS proposal. The discovery potential of such instrumentation appears exciting, ranging from observation of new astrophysical and cosmological sources, as well as searches for ultralight dark matter.
Holder,JamieUniversity of DelawareUnderstanding the Origin and Impact of Relativistic Cosmic Particles with Very-High-Energy Gamma-rays
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This white paper briefly summarizes the importance of the study of relativistic cosmic rays, both as a constituent of our Universe, and through their impact on stellar and galactic evolution. The focus is on what can be learned over the coming decade through ground-based gamma-ray observations over the 20 GeV to 300 TeV range.
Holder,GilbertUniversity of Illinois at Urbana-ChampaignTracking the time-variable Millimeter-wavesky with CMB experiments
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Cosmic microwave background experiments make wide-area, sensitive, high-cadence maps of the sky at mm-wavelengths. Discoveries will include moving (solar system objects), time-variable (stars, active galactic nuclei), or transient sources (novae, tidal disruption events, gamma-ray bursts, nearby supernovae, gravitational wave events) .
Holland,WayneUK Astronomy Technology Centre, Royal Observatory, Edinburgh, UKDebris disks: Exploring the environment and evolution of planetary systems
.pdf
This paper focusses on the prospects for observations of debris disks in the submillimeter region, and outlines the direction the research is likely to take in the next decade.
Holler,BryanSTScI"It’s full of asteroids!”: Solar system science with a large field of view
.pdf
Next-generation space telescopes will have larger apertures, larger fields of view, and more sensitive instrumentation than their predecessors. The prospects for solar system science with these facilities are substantial, particularly in the area of space-based surveys for the detection of new minor bodies and irregular satellites.
Horzempa,PhilipLeMoyne CollegeHigh Definition Astrometry
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High Definition Astrometry (0.1 - 1.0 micro-arcseconds) will open a new window into neighboring planetary systems. The realm of temperate terrestrial worlds can be surveyed. This includes Earth Analogs, thereby allowing the value of eta-Earth to be directly determined. It will be able to confirm the existence of Radial Velocity (RV) planets.
Hosek,MatthewUCLAStar Formation in Different Environments: The Initial Mass Function
.pdf
We discuss new opportunities for measuring the Initial Mass Function across a wide range of environments in the coming decade with JWST, WFIRST, and thirty-meter class telescopes.
Hu,RenyuJet Propulsion LaboratoryThe Super-Earth Opportunity – Search for Habitable Exoplanets in the 2020s
.pdf
The science return of detecting temperate exoplanets as large as 2 Re should be considered as one of the primary evaluation criteria to assess exoplanet missions. Given the implications on the size of space telescopes, this evaluation criteria should be applied independently from the assessment of capability to find a true Earth analog.
Huber,DanielInstitute for Astronomy, University of HawaiiStellar Physics and Galactic Archeology using Asteroseismology in the 2020's
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Asteroseismology is the only observational tool in astronomy that can probe the interiors of stars, and is a benchmark method for deriving fundamental properties of stars and exoplanets. In this white paper, we describe key science questions and necessary facilities to continue the asteroseismology revolution into the 2020's.
Huff,EricJet Propulsion LaboratoryGalaxy Kinematics and the Future of Dark Energy
.pdf
We describe how galaxy kinematics can be used to greatly reduce statistical and systematic errors in weak lensing. We point out the ways in which these gains could allow kinematic lensing surveys to go beyond the limits on what is achievable with current methods, and we advocate for support for studies and instrumentation to advance the method.
Hunter,ToddNational Radio Astronomy ObservatoryUnderstanding Accretion Outbursts in Massive Protostars through Maser Imaging
.pdf
Two recent extraordinary accretion outbursts in massive protostars, both heralded by maser flares, have impacted our view of star formation. Unraveling the accretion mechanism in such deeply-embedded systems requires larger, more sensitive centimeter wavelength interferometers to image the masing molecular gas simultaneously with the ionized gas.
Hutter,AnneKapteyn Astronomical Institute, University of GroningenA proposal to exploit galaxy-21cm synergies to shed light on the Epoch of Reionization
.pdf
This white paper outlines the benefits of synergizing WFIRST, Subaru Hyper Suprime-Cam or other >25m-class telescopes galaxy observations with SKA 21cm measurements to constrain the nature of reionization (ionization history and topology) and its sources.
Isella,AndreaRice UniversityObserving Planetary Systems in the Making
.pdf
We discuss science cases to support the development of sub-au imaging capabilities to image forming planets in the terrestrial region of nearby proto-planetary disks.
Jackson,JamesUSRAFar-Infrared studies of Star and Planet Formation
.pdf
Far-infrared observations of star-forming regions trace the star-forming material density and temperature as well as the shape of the magnetic field (through polarization of dust thermal continuum). Far-infrared spectroscopy of disks around young stars can reveal the initial conditions of planet formation.
James,BethanSpace Telescope Science InstituteSpatially Resolved UV Nebular Diagnostics in Star-Forming Galaxies
.pdf
This paper describes the need for spatially resolved rest-frame UV spectroscopy across nearby SFGs via a space-based UV-IFU. Such observations will robustly constrain the diagnostic tools critical to understanding fundamental questions concerning the evolution, physical conditions, and ionization structure of SFGs across cosmic time.
Jang-Condell,HannahUniversity of WyomingProtoplanetary Disk Science Enabled by Extremely Large Telescopes
.pdf
We discuss how a spectroscopic and imaging survey of protoplanetary disks with Extremely Large Telescopes will enhance our understanding of planet formation by (1) measuring the physical and chemical conditions in disks using infrared spectroscopy and (2) studying planet-disk interactions using imaging and spectro-astrometry.
Ji,HantaoPrinceton UniversityMajor Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena throughout the Universe
.pdf
This is a group white paper of 100 authors (each with explicit permission via email) from 51 institutions on the topic of magnetic reconnection which is relevant to 6 thematic areas. Grand challenges and research opportunities are described in observations, numerical modeling and laboratory experiments in the upcoming decade.
Ji,AlexanderCarnegie ObservatoriesLocal Dwarf Galaxy Archaeology
.pdf
Local dwarf galaxies retain a record of high-redshift and metal-poor stellar populations. Resolved stellar spectroscopy provides insights into the first stars and galaxies, the smallest dark matter halos, and the first stellar explosions. ELTs with multi-object R=5k-30k spectroscopy will enable such studies for galaxies throughout the Local Group.
Johnson,MarshallThe Ohio State UniversityTracing the Origins and Evolution of Small Planets using Their Orbital Obliquities
.pdf
We recommend an intensive effort to survey the orbital obliquity distribution of small close-in exoplanets over the coming decade. This is a key tracer of how planets form and migrate. Over the next decade we can observe hundred of planets as small as ~2 REarth, opening a window into the orbital properties of the most common planets.
Johnson,MeganUnited States Naval ObservatoryThe Next Generation Celestial Reference Frame
.pdf
Astrometry is the fundamental cornerstone for all areas of Astronomy. The IAU adopted International Celestial Reference Frame (ICRF) consists of radio positions of 4536 quasars. In order to maintain and improve the accuracy of the ICRF, we require a next generation radio telescope with long baselines and high sensitivity such as the ngVLA.
Johnson,JenniferOhio State UniversityThe Origin of the Elements Across Cosmic Time
.pdf
This white paper describes the current advances in our understanding of the origin of the elements, lists important outstanding issues, discusses the implications for improving our knowledge, and describes the capabilities needed to make progress over the next decade.
Juanola-Parramon,RoserNASA GSFC/UMBCSolar System Science with Space Telescopes
.pdf
Building on the legacy of HST and other space telescopes, a large multi-wavelength space observatory would enable transformative advances in planetary science. Here we highlight several representative areas of Solar System science that would greatly benefit from high resolution UV/Opt/NIR imaging (Venus, Jupiter, Neptune, dwarf planets and KBOs).
Kalogera,VassilikiNorthwestern U.The Yet-unobserved Multi-Messenger Gravitational-Wave Universe
.pdf
Observations with next-generation ground-based detectors further enhanced with multi-messenger (electromagnetic and neutrino) detections will allow us to probe new extreme astrophysics. Target sources included: core-collapse supernovae, continuous emission from isolated or accreting neutron stars, and bursts from magnetars and other pulsars.
Kalogera,VickyNorthwestern U.Deeper, Wider, Sharper: Next-Generation Ground-based Gravitational-Wave Observations of Binary Black Holes
.pdf
Next-generation observations will revolutionize our understanding of binary black holes and will detect new sources, such as intermediate-mass black holes. Primary science goals include: Discover binary black holes throughout the observable Universe; Reveal the fundamental properties of black holes; Uncover the seeds of supermassive black holes.
Kamraj,NikitaCalifornia Institute of TechnologyProbing the Physical Properties of the Corona in Accreting Black Holes
.pdf
This white paper explores our current understanding of the corona in Active Galactic Nuclei and discusses important questions to be addressed in the coming decade surrounding the nature of the corona.
Kane,StephenUniversity of California, RiversideVenus as a Nearby Exoplanetary Laboratory
.pdf
Venus provides a unique opportunity to explore the processes that create hostile environments and define the boundaries of habitability. We advocate a continued comprehensive study of our sister planet, including models of early atmospheres, compositional abundances, and Venus-analog frequency analysis from current and future exoplanet data.
Kao,Der-youNASA Goddard Space Flight Center/ Universities Space Research AssociationImpacts of Quantum Chemistry Calculations on Exoplanetary Science, Planetary Astronomy, and Astrophysics
.pdf
Quantum chemical simulations have matured enough to describe real systems with an accuracy that competes with experiments. Several existing quantum chemical studies supporting exoplanetary science are described, and the potential impacts of improved models associated with scientific goals of missions are addressed.
Kao,MelodieArizona State UniversityMagnetism in the Brown Dwarf Regime
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A suite of discoveries in the last two decades demonstrate that we are now at a point where incorporating magnetic behavior is key for advancing our ability to characterize substellar systems. Investing now in brown dwarf magnetism will provide a key platform for exploring exoplanetary magnetism and habitability beyond the solar system.
Kara,ErinUniversity of Maryland, NASA GSFC, MITX-ray follow-up of extragalactic transients
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Most violent and energetic processes in our universe, including mergers of compact objects, explosions of massive stars and extreme accretion events, produce copious amounts of X-rays. We identify key questions about several extragalactic multi-messenger and multi-wavelength transients, and demonstrate how X-ray followup answers these questions.
Kartaltepe,JeyhanRochester Institute of TechnologyAssembly of the Most Massive Clusters at Cosmic Noon
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The next decade will see a transformational shift in our understanding of protoclusters as deep spectroscopy over wide fields of view will be possible in conjunction with high resolution deep imaging in the optical and near-infrared, enabling the characterization of their overall structure, the galaxies within them, and the gas that feeds them.
Kashlinsky,AlexanderGoddard Space Flight CenterPopulations behind the source-subtracted cosmic infrared background anisotropies
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Source-subtracted CIB fluctuations cannot be explained by known galaxy populations and appear highly coherent with unresolved CXB from significantly abundant accreting BHs. Characterizing the CIB with high accuracy, and constraining the nature of the new populations would produce critically important cosmological information in the next decade.
Kashlinsky,AlexanderGoddard Space Flight CenterElectromagnetic probes of primordial black holes as dark matter
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Next decade, new space- and ground-borne electromagnetic instruments, combined with concurrent theoretical efforts, should shed critical light on the link between primordial Black Holes and Dark Matter. We summarize the prospects to resolve this important issue with electromagnetic observations using instruments and tools expected in the 2020’s.
Kasliwal,MansiCalifornia Institute of TechnologyThe Dynamic Infrared Sky
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Opening up the dynamic infrared sky for systematic time-domain exploration would yield many scientific advances in multi-messenger astrophysics, stellar evolution and high energy physics. We discuss challenges and pathfinders to overcome them. We conclude with recommendations on both infrared discovery and follow-up to flourish in the next decade.
Kastner,JoelRochester Institute of TechnologyThe Early Evolution of Stars and Exoplanet Systems: Exploring and Exploiting Nearby, Young Stars
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We describe how our understanding of a wide range of aspects of the astrophysics of young stars and planetary systems is ripe for progress over the next decade via the identification and study of nearby (D <= 120 pc), young (age < 750 Myr) stars with present and next-generation facilities and instruments.
Kataria,TiffanyJet Propulsion Laboratory, California Institute of TechnologyThe Mid-Infrared Search for Biosignatures on Temperate M-Dwarf Planets
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In this science white paper, we present the importance of transiting planets in understanding habitability, and how the mid-infrared provides a unique spectroscopic window to the most prominent signatures of life. We recommend the development of a large space-based IR telescope to conduct high-precision spectroscopy over a broad wavelength range.
Kauffmann,JensHaystack Observatory, Massachusetts Institute of TechnologyImaging Entire Molecular Clouds in many Lines: Formation of Stars and Planets
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Studies of molecular line emission at >70 GHz will substantially advance our picture of how stars from in the molecular clouds of the Milky Way. Such work requires spatially resolved imaging of entire clouds at ~0.1 pc resolution. This work requires both small and large telescopes, as well as ALMA.
Kauffmann,JensHaystack Observatory, Massachusetts Institute of TechnologyImaging Entire Molecular Clouds in many Lines: From the Milky Way to Galaxies
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Emission lines from molecules at frequencies >70 GHz allow astronomy to explore how star formation depends on molecular cloud conditions, and how cloud conditions vary within galaxies. However, comprehensive observations of the Milky Way are needed to refine lines as probes of gas conditions. Such work requires both large and small telescopes.
Kelley,LukeNorthwestern UniversityMulti-Messenger Astrophysics With Pulsar Timing Arrays
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Pulsar timing arrays are on the verge of detecting low-frequency gravitational waves from supermassive black hole binaries. Multi-messenger observations will revolutionize our understanding of: 1. co-evolution of BHs with their hosts, 2. interactions of binaries with their environments, 3. fundamental physics of accretion, 4. cosmological distances
Kieda,DavidUniversity of UtahScience opportunities enabled by the era of Visible Band Stellar Imaging with sub-100 μarc-sec angular resolution.
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This white paper briefly summarizes stellar science opportunities enabled by ultra-high resolution (sub-100 μ arc-sec) astronomical imaging in the visible (U/V) wavebands. We describe the science impact of imaging of several thousand bright (m< 6), hot (O/B/A) stars using a modern implementation of Stellar Intensity Interferometry (SII).
Kierans,CarolynNASA/Goddard Space Flight CenterPositron Annihilation in the Galaxy
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The 511 keV line from positron annihilation in the Galaxy was detected ~50 years ago, but the source of positrons is still unconfirmed and remains one of the enduring mysteries in gamma-ray astronomy. We will summarize the current knowledge base of Galactic positrons, and discuss how next-generation instruments could finally provide the answers.
Kim,AlexLawrence Berkeley National LaboratoryTesting Gravity Using Type Ia Supernovae Discovered by Next-Generation Wide-Field Imaging Surveys
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In the next decade the peculiar velocities of SNe~Ia in the local $z<0.3$ Universe will provide a measure of $gamma$ to $pm 0.01$ precision that can definitively distinguish between General Relativity and leading models of alternative gravity.
Kirkpatrick,J.DavyCaltech/IPACThe Need for Infrared Astrometry of Brown Dwarfs in the Post-Gaia Era
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Brown dwarf research in the next decade will be reliant on extending high-precision astrometry in wavelength and temporal coverage. Future astrometry will enable measures of the low-mass cutoff of star formation, allow for the discovery of cold brown dwarf analogs to cold (exo)planets, and enable mass measurements for single and binary systems .
Kirkpatrick,J.DavyCaltech/IPACOpportunities in Time-domain Stellar Astrophysics with the NASA Near-Earth Object Camera (NEOCam)
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NEOCam will provide valuable data for the discovery and characterization of cold brown dwarfs, exoplanet analogs with weather variations, pre-main sequence variables, infrared-only transients, and more. For a relatively small investment, NASA can realize the full potential of NEOCam data by providing additional data products and transient alerting.
Kishimoto,MakotoKyoto Sangyo UniversityExploring Active Supermassive Black Holes at 100 Micro-arcsecond Resolution
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Super-high spatial resolution observations in the infrared are now enabling major advances in our understanding of supermassive black hole systems at the centers of galaxies. We describe the discovery potential of the current and future long-baseline interferometry in the infrared in this field.
Kobelski,AdamWest Virginia UniversityHigh Frequency Solar Observing at the Green Bank Observatory
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Here we discuss the utility of performing high frequency observations of the solar chromosphere with the 100 m Green Bank Telescope at 100 GHz.
Koekemoer,AntonSpace Telescope Science InstituteUltra Deep Field Science with WFIRST
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This whitepaper motivates an Ultra-Deep Field survey with WFIRST, covering at least ~100x the area of the HUDF, up to ~1 sq deg, to mag ~30, potentially revealing thousands of galaxies and AGN at the faint end of the LF, at or beyond z~10 in the epoch of reionization, and dramatically increasing the discovery potential at these redshifts.
Kohno,KotaroThe University of TokyoExploration and characterization of the earliest epoch of galaxy formation: beyond the re-ionization era
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Recent ALMA detection of the bright [OIII] 88 um line at z = 9.11, indicates the onset of star formation at z~15. In order to uncover a large number of z=10-15 galaxies, we argue two possible pathways: (1) a blind spectroscopic survey of [OIII] 88 um line emitters, and (2) a high-cadence survey of transient sources to catch the pop-III GRBs.
Kollmeier,JunaCarnegie Institution for SciencePrecision Stellar Astrophysics and Galactic Archeology: 2020
.pdf
This white paper is meant to capture many different elements of stellar astrophysics and galactic archeology that highlight the important role this science will play in the 2020s era of precision astronomy.
Kopparapu,Ravi kumarNASA Goddard Space Flight CenterExoplanet Diversity in the Era of Space-based Direct Imaging Missions
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This whitepaper discusses the diversity of exoplanets that could be detected by future observations in the upcoming era of large space-based flagship missions. The primary focus will be on characterizing Earth-like worlds around Sun-like stars. However, we will also be able to characterize companion planets in the system simultaneously.
Koss,MichaelEureka ScientificBlack Hole Growth in Mergers and Dual AGN
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Galaxy mergers are predicted to represent a significant stage of SMBH growth. This white paper discusses the key questions in galaxy mergers, dual, and offset AGN, and proposes solutions using future high-resolution multiwavelength observatories in the X-rays (AXIS, Lynx), NIR and MIR (JWST and 30-meter class telescopes), and submillimeter (ALMA).
Kovetz,ElyBen-Gurion UniversityAstrophysics and Cosmology with Line-Intensity Mapping
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We discuss how Line-Intensity Mapping - an emerging technique to measure the spatial fluctuations in the integrated emission from spectral lines originating from many individually unresolved galaxies and the diffuse intergalactic medium - can uniquely address a list of major open questions in Galaxy Evolution and Cosmology and Fundamental Physics.
Kowalski,AdamUniversity of Colorado, National Solar ObservatoryDeveloping a vision for exoplanetary transit spectroscopy: a shared window on the analysis of planetary atmospheres and of stellar magnetic structure
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We describe how accurate exoplanet atmospheres’ characterization will inevitably require taking into consideration stellar inhomogeneities caused by convection and magnetic fields. Disentangling hese two components requires a multipronged approach with new solar reference spectra, MHD modeling, and collaborations among astrophysics communities.
Krawczynski,HenricWashington University in Saint LouisUsing X-Ray Polarimetry to Probe the Physics of Black Holes and Neutron Stars
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This white paper highlights compact object and fundamental physics science opportunities afforded by high-throughput broadband (0.1-60 keV) X-ray polarization observations. The polarimetric observations can reveal the inner workings of high-energy sources, and allow us to test physical laws in the extreme conditions close to compact objects.
Kreckel,KathrynMax Planck Institute for AstronomyMapping Gas Phase Abundances and Enrichment Patterns Across Galaxy Disks
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In the coming decade we will map abundances of 1000s of HII regions within galaxies. This will allow us to understand the role of feedback and turbulence in driving the mixing and diffusion of metals in the ISM, search for over- and under-enriched regions, and resolve systematic uncertainties plaguing nebular abundance diagnostics.
Krissansen-Totton,JoshuaUniversity of WashingtonAtmospheric disequilibrium as an exoplanet biosignature: Opportunities for next generation telescopes
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We explore atmospheric chemical disequilibrium as an exoplanet biosignature and argue that a CH4+CO2 combination could be a common sign of life on planets with oxygen-free atmospheres such as the ancient Earth. This biosignature combination is potentially detectable with JWST and readily detectable with some next generation space-based telescopes.
Kupfer,ThomasKavli Insitute for Theoretical Physics / UC Santa BarbaraA Summary of Multimessenger Science with Galactic Binaries
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Galactic binaries with orbital periods less than ≈1hr are strong gravitational wave sources in the mHz regime, ideal for LISA. In this white paper we present an overview of the opportunities for research on Galactic binaries using multi-messenger observations and summarize some recommendations for the 2020 time-frame.
Kurtz,MichaelCenter for Astrophysics | Harvard & SmithsonianFrom Dark Energy to Exolife: Improving the Digital Information Infrastructure for Astrophysics
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A robust information infrastructure is needed to meet future research challenges. The scientific literature can be used as the central organizing point used to navigate interdisciplinary research fields. Connecting the literature with data products increases discoverability of both and allows for the data to be more accessible by non-experts.
La Plante,PaulUniversity of PennsylvaniaMapping Cosmic Dawn and Reionization: Challenges and Synergies
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Cosmic dawn and the Epoch of Reionization are among the least explored observational eras in cosmology. To maximize scientific discovery and return on investment, coordinated survey planning and joint data analysis from experiments probing this epoch should be a high priority, closely coupled to the computational models and theoretical predictions.
Laha,SibasishUniversity of California, San DiegoThe physics and astrophysics of X-ray outflows from Active Galactic Nuclei.
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AGN outflows are integral for understanding how the central super massive black hole interacts with the host galaxy and co-evolves in cosmic time. This white paper sets the primary science goals for the next decade and suggests the key parameters on which the next generation X-ray telescopes should be built to revolutionize our understanding.
Law,CaseyUC BerkeleyRadio Time-Domain Signatures of Magnetar Birth
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We consider the implications of an emerging consensus on the origin of a diverse set of luminous astrophysical transients, such as FRBs, SLSNe, and ULGRBs. Each of these classes could be interpreted as a signature of magnetar birth. We describe how radio transients from milliseconds to gigaseconds will be used to address diverse physical questions.
Lazio,JosephJet Propulsion Laboratory, California Institute of TechnologyMagnetic Fields of Extrasolar Planets: Planetary Interiors and Habitability
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Generated by internal dynamos, magnetic fields are one of the few remote sensing means of constraining the properties of planetary interiors. The Earth's magnetic field has been speculated to be partially responsible for its habitability, and knowledge of an extrasolar planet’s magnetic field may be necessary to assess its habitability.
Lebouteiller,VianneyLaboratoire AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, F-91191 Gif-sur-Yvette, FranceISM and CGM in external galaxies
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We describe possible avenues for measuring properties of the interstellar and circumgalactic medium (ISM, CGM) in external galaxies through far-UV absorption lines. We discuss in particular chemical abundances, the molecular gas reservoir and the thermal balance in the metal-poor ISM and the kinematics and ionization structure of the CGM.
Lee,Chien-HsiuNOAOIdentification and characterization of the host stars in planetary microlensing with ELTs
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We propose to robustly and routinely measure the masses of exoplanets beyond 1 AU from their host stars with the microlensing method, by directly imaging the host star with ELTs. A direct result from this project will be planet occurrence rate beyond the snow line, which will enable us to discern different planet formation mechanisms.
Leggett,SandyGemini Observatory Northern OperationsDiscovery of Cold Brown Dwarfs or Free-Floating Giant Planets Close to the Sun
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This White Paper describes the opportunities for discovery of Jupiter-mass objects with 300K atmospheres. The discovery and characterization of such cold objects is vital for understanding the low-mass terminus of the initial mass function and for optimizing the study of exoplanets by the next generation of telescopes, space probes and missions.
Lehner,NicolasUniversity of Notre DameFollowing the Metals in the Intergalactic and Circumgalactic Medium over Cosmic Time
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Metal enrichment throughout the universe offers a unique probe of the large-scale gas flows governing galaxy evolution. We argue that fully tracking metals through galaxies, the circumgalactic and intergalactic media will require a large telescope with a FUV/NUV high-resolution spectrograph and science-ready archives for ground-based observatories.
Lemoine-Busserolle,MarieGemini ObservatoryThe Evolution of the Tully-Fisher Relation: Characterizing the Assembly of Rotation-Dominated Disk Galaxies over cosmic time
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We describe how to examine the properties of rotation-dominated (RD) disk galaxies over cosmic time by probing a large range in mass and luminosity, down to the sub-L* population. The science goal is to characterize the evolution of RD disk galaxies. This white paper pertains to the “Galaxy evolution” panel of the Astro2020 Decadal Survey.
Leroy,AdamOhio State UniversityPhysical Conditions in the Cold Gas of Local Galaxies
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We describe a next major frontier in studies of galaxy evolution and star formation: linking physical conditions in the cold, star-forming interstellar medium to host galaxy and local environment. The key observations will be cm-, mm-, and submm-wave spectroscopy and spectroscopic imaging. We highlight key paths for progress in the next decade.
Lesyna,LarryLXL TechnologyA Technosignature Carrying a Message Will Likely Inform us of Crucial Biological Details of Life Outside our Solar System
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We should search for interstellar messages because they probably contain a rich source of biological information about extraterrestrial life.
Leutenegger,MauriceNASA/GSFCThe crucial role of high resolution X-ray spectroscopy in studies of massive stars and their winds
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High-resolution X-ray spectroscopy has proven to be a crucial tool for addressing a wide range of problems relating to massive stars. New X-ray observatories featuring high resolution spectroscopy with square meter collecting area are required.
Li,TingFermi National Accelerator LaboratoryDark Matter Physics with Wide Field Spectroscopic Surveys
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This white paper summarizes the astronomical observations for next decade to probe the particle properties of dark matter, and concludes that a 10m class wide-field, high-multiplex spectroscopic survey facility is required for the next decade to definitively search for deviations from the cold collisionless dark matter model.
Line,MichaelArizona State UniversityThe Importance of Thermal Emission Spectroscopy for Understanding Terrestrial Exoplanets
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The primary objective of this white paper is to illustrate the importance of the thermal infrared in characterizing terrestrial planets leveraging our experience in characterizing extra-solar jovian worlds.
Lis,DariuszCaltechD/H Ratio in Water and the Origin of Earth’s Oceans
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Measurements of the D/H ratio in cometary water provide key constraints on the origin and history of water, and the contribution of comets to Earth’s oceans. Measurement of the D/H ratio in a statistically significant sample of comets is as a high-priority goal for the next decade, important for understanding Earth’s habitability.
Lisman,DougJet Propulsion Laboratory, California Institute of TechnologySurveying the solar neighborhood for ozone in the UV at temperate rocky exoplanets
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This whitepaper shows ozone to be the best potential biosignature gas for an early exoplanet imaging mission. While oxygen is not detectable at Earth until about 0.5 Ga, its proxy ozone is detectable for about half of that history. Ozone’s pronounced UV feature yields a small starshade and telescope and a simple photometer instrument.
Littenberg,TysonNASA Marshall Space Flight CenterGRAVITATIONAL WAVE SURVEY OF GALACTIC ULTRA COMPACT BINARIES
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Summary of science yield from joint GW and EM surveys of ultracompact binaries in the galaxy, including studies of the population as a whole and the dynamics of individual systems.
Liu,AdrianMcGill UniversityCosmology with the Highly Redshifted 21 cm Line
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The 21cm line can be used to conduct large-volume surveys of the high-z universe, probing both astrophysics and cosmology. We highlight the promise of using the 21cm line to constrain cosmology via z>6 observations, emphasizing the key advances and investments required to access the potentially vast information content of future surveys.
Lockman,FelixGreen Bank ObservatoryHigh velocity Clouds: Building Blocks of the Local Group?
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High velocity clouds (HVCs) are gaseous objects with unusual velocities that lie in the halo of the Milky Way and can be used to trace the exchange of gas between disk and halo, accretion of new gas, and tidal streams. IHVCs are key to understanding the relationship between Galactic disks and their halos.
Lonsdale,ColinMIT Haystack ObservatoryStudying the magnetized ISM with all-sky polarimetric radio maps
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This paper describes the scientific utility of all-sky mapping at low radio frequencies, for improving our understanding of the interstellar medium. With matched resolution across a wide frequency range, precision calibration, and polarimetry, qualitatively new studies of importance will be enabled. The necessary technology is swiftly maturing.
Lopez,LauraThe Ohio State UniversitySupernova Remnants in High Definition
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Supernova remnants (SNRs) offer the means to study SN explosions, dynamics, and shocks at sub-parsec scales. In this white paper, we discuss the major advances possible with X-ray spectro-imaging at arcsecond scales, with a few eV spectral resolution and a large effective area.
Lopez,EricNASA Goddard Space Flight CenterUnderstanding Exoplanet Atmospheres with UV Observations II: The Far UV and Atmospheric Escape
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In this white paper we focus on the science case for exoplanet observations in the far-UV (FUV); an accompanying white paper led by Jessie Christiansen will focus on the science case in the NUV and blue/optical.
Lopez-Morales,MercedesCenter foe Astrophysics | Harvard & SmithsonianDetecting Earth-like Biosignatures on Rocky Exoplanets around Nearby Stars with Ground-based Extremely Large Telescopes
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As we begin to discover rocky planets in the habitable zone of nearby stars, we will need quick advancements on instrumentation and observational techniques that will enable us to answer how similar or dissimilar are those planets to Earth? Ground-based ELTs combined with future space missions will be key to detect biosignatures.
Lopez-Rodriguez,EnriqueSOFIA Science Center / NASA AMES CenterTracing the feeding and feedback of active galaxies
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Active galaxies accrete mass from their surroundings, and inject energy and mass to the galactic medium through outflows. The interface between the active galaxy and host galaxy is a region of a few pc in size with a gas and dust flow cycle. In the coming decade, we will demonstrate more directly the active role of the torus in galaxy evolution.
Lorimer,DuncanWest Virginia UniversityRadio Pulsar Populations
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We provide an overview of the radio pulsar population as it is currently understood, and give predictions for surveys with predominantly large single-dish radio facilities over the coming decade. Over 10,000 pulsars are expected to be found. Applications include tests of gravity and as natural laboratories for low-frequency gravitational waves.
Lovell,AmyAgnes Scott CollegeGround-based Observations of Small Solar System Bodies: Probing Our Local Debris Disk
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Comets and asteroids are a window into the formation, evolution, and dynamic environment of our solar system, an end-state of debris disks that we can only study from afar. Long-wavelength radio ground-based observations of asteroids and comets provide an excellent complement to shorter-wavelength observations both from the ground and from space.
Lu,JessicaUC BerkeleyFrom Stars to Compact Objects: The Initial-Final Mass Relation
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We lack a predictive model for how a star of a given mass explodes and what kind of remnant it leaves behind (i.e. the initial-final mass relation, IFMR). Astrometric gravitational lensing offers a new way to find and weigh compact objects and place the first constraints on the IFMR, compact object multiplicity, and kick velocities.
Lunine,JonathanCornell UniversityComparing key compositional indicators in Jupiter with those in extra-solar giant planets.
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James Webb Space Telescope will enable detailed analysis of molecular abundances, including but not limited to all the major carbon- and oxygen-bearing species in hot Jupiter atmospheres. This will allow determination of the carbon-to-oxygen ratio, an essential number for planet formation models and allowing comparison with Juno’s value for Jupiter.
Lynch,RYanGreen Bank ObservatoryThe Virtues of Time and Cadence for Pulsars and Fast Transients
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We summarize the scientific opportunities that can be realized using pulsars and fast radio transients with high-cadence, long duration observing programs and data sets, with a particular focus on gravitational waves, fundamental physics, pulsar emission, the dynamical interstellar and intergalactic media, and fast radio bursts.
Lyra,WladimirCalifornia State University, NorthridgePlanet formation – The case for large efforts on the computational side
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As advances are expected with ground based interferometers and the James Webb Space Telescope in the next decade, the central point of this white paper is what efforts on the computational side are required in the next decade to advance our theoretical understanding, explain the observational data, and guide new observations?
Maccarone,ThomasTexas Tech UniversityCompact Stellar Jets
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Jets produced by compact stars are the ideal laboratories for understanding jets in general due to the ability to measure accretors properties accurately, and the short timescales of variability of the systems. We outline what is needed to move forward with understanding jet production in X-ray binaries.
Maccarone,ThomasTexas Tech UniversityPopulations of Black holes in Binaries
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This paper outlines the importance of understanding the mass distributions, spin distributions, and natal kick distributions of compact objects, with an emphasis on black holes. It discusses means to improve sizes of source populations and understanding of key source parameters.
Mandelbaum,RachelCarnegie Mellon UniversityWide-field Multi-object Spectroscopy to Enhance Dark Energy Science from LSST
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This white paper describes the opportunities to greatly improve measurements of cosmological parameters from LSST made possible by community access to wide-field (>20 sq. deg. total area), highly-multiplexed OIR multi-object spectroscopy (MOS) on 4-15m telescopes. Companion papers discuss opportunities from deeper MOS and single-object data.
Mantz,AdamKIPAC, Stanford UniversityThe Future Landscape of High-Redshift Galaxy Cluster Science
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We describe the opportunities for galaxy cluster science in the high-redshift regime where massive, virialized halos first formed and where star formation and AGN activity peaked. New observing facilities from radio to X-ray wavelengths, combining high spatial/spectral resolution with large collecting areas, are poised to uncover this population.
Margot,Jean-LucUniversity of California, Los AngelesStructure of terrestrial planets and ocean worlds
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Rotation studies provide a unique window on the interior structure of planetary bodies. The science can be accomplished only with facilities that enable many other astronomical observations. The Astro2020 decadal survey will make recommendations about the facilities that are critical to the realization of the science described in this white paper.
Margot,Jean-LucUniversity of California, Los AngelesThe radio search for technosignatures in the decade 2020–2030
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Advancing the scientific frontier in the search for life in the universe requires support of searches for both biosignatures and technosignatures. A modest budgetary increment can expand the search for life in the universe from primitive to complex life and from the solar neighborhood to the entire Galaxy.
Marin,FrédéricUniversité de Strasbourg, CNRS, Observatoire Astronomique de Strasbourg, UMR7550, F-67000 Strasbourg, FranceThe role of Active Galactic Nuclei in galaxy evolution: insights from space ultraviolet spectropolarimetry
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Although the global properties of Active Galactic Nuclei (AGN) seem today rather understood, the details of AGN physics and the impact of AGN on galaxy evolution are still poorly constrained. We describe how a space telescope with a large collecting area able to provide UV spectropolarimetry can help us make great progress in this area.
Markevitch,MaximNASA GSFCPhysics of cosmic plasmas from high angular resolution X-ray imaging of galaxy clusters
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The paper presents possibilities for measuring several fundamental properties of cosmic plasmas via high angular resolution, high collecting area, low background X-ray imaging of galaxy clusters, building upon some trailblazing measurements performed by the Chandra X-ray Observatory.
Marley,MarkNASA Ames Research CenterImaging Cool Giant Planets in Reflected Light: Science Investigations and Synergy with Habitable Planets
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Photometric and spectroscopic observations of cool extrasolar giant planets are valuable both for understanding the origin and evolution of giant planets as a whole and for preparing for the interpretation of similar datasets from potentially habitable extrasolar terrestrial planets in the decades to follow.
Martin,ChristopherCalifornia Institute of TechnologyIGM and CGM Emission Mapping: A New Window on Galaxy and Structure Formation
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We describe the prospects for IGM and CGM emission mapping with UV resonance lines at low and high redshift. There are 5 key science questions that will be addressed: 1) A Lyman alpha emission calibration; 2) physical properties of galaxy halos; 3) the role and nature of gas inflows to galaxies; 4) gas outflows: 5) emission from the cosmic web.
Martinez Pillet,ValentinNational SOlar ObservatorySynoptic Studies of the Sun as a Key to Understanding Stellar Astrospheres
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Ground-based solar observations provide key contextual data (i.e., the “big picture”) to produce a complete description of the only astrosphere we can study in situ: our Sun’s heliosphere. This white paper outlines the current paradigm for ground-based solar synoptic observations, and indicates those areas that will benefit from focused attention.
Matra,LucaCenter for Astrophysics | Harvard & SmithsonianExocometary Science
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This paper describes recent advances that led to the emergence of Exocometary Science, with an outlook and recommendations for the field to prospect in future decades. These studies provide a window into the composition and dynamics of exocomets, extrasolar icy minor bodies, as observed at the epoch of volatile delivery to inner rocky planets.
Matsuura,MikakoCardiff UniversityDust in supernovae: --- Do supernovae produce the first dust in the Universe? Are supernovae the key dust producers of galaxies?
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This White Paper debates whether supernovae produce the first dust in the Universe, and how this debate will be tested with forthcoming telescopes.
Matthews,Lynn D.Massachusetts Institute of Technology Haystack ObservatoryMolecular Masers as Probes of the Dynamic Atmospheres of Dying Stars
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The atmospheres of mass-losing red giants are characterized by the interplay between complex and dynamic processes. In the coming decade, observations of the molecular masers in the outflows of evolved stars with ultra-high angular resolution using VLBI are poised to provide groundbreaking insights into the physics of late-stage stellar mass-loss.
Matthews,Lynn D.Massachusetts Institute of Technology Haystack ObservatoryUnlocking the Secrets of Late-Stage Stellar Evolution and Mass Loss through Radio Wavelength Imaging
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Many details concerning the physics of late-stage stellar mass loss remain poorly understood. Observations at cm, mm, and sub-mm wavelengths that resolve the radio surfaces and extended atmospheres of evolved stars in space, time, and frequency are poised to provide groundbreaking new insights into these questions in the coming decade.
Mazin,BenUniversity of California Santa BarbaraDirectly Imaging Rocky Planets from the Ground
.pdf
An exploration of the exoplanet science possible using ground-based 30-m class telescopes.
McArthur,BarbaraUniversity of Texas at AustinAll-Sky Near Infrared Space Astrometry
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An all-sky near infrared (NIR) space observatory operating in the optical NIR, separated in time from the original Gaia would provide microarcsecond NIR astrometry and millimag photometry to penetrate obscured regions unraveling the internal dynamics of the Galaxy.
McCandliss,StephanJohns Hopkins UniversityLyman continuum observations across cosmic time: recent developments, future requirements
.pdf
Quantifying the physical conditions that allow radiation emitted shortward of the hydrogen ionization edge at 911.7 Å to escape the first collapsed objects and ultimately reionize the universe is a compelling problem for astrophysics. Multi-object spectroscopy from facility class telescopes are required.
McConnell,MarkUniversity of New Hampshire / Southwest Research InstitutePrompt Emission Polarimetry of Gamma-Ray Bursts
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Many aspects of astrophysical jets can be studied by measuring the polarization of the prompt emission from GRBs. Theoretical models show that a more complete understanding of the inner structure of GRBs, including the geometry and physical processes close to the central engine, can only be achieved by gamma-ray polarimetry.
McGehee,PeregrineCollege of the CanyonsDynamical Processes in the Planet-Forming Environment
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The transfer of circumstellar disk mass and momentum onto the protostar and out into the environment occurs via a variety of mechanisms including magnetospheric accretion, jets,outflows, and disk winds. Metallic emission lines, along with the Balmer series of hydrogen, probe the kinematics of gas within the planet-forming regions of the disks.
McGuire,BrettNational Radio Astronomy ObservatoryLifting the Veil on Aromatic Chemistry: Complex Carbon Across the Stellar Life Cycle from Birth to the Afterlife
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Here, we outline the observational, laboratory, and modeling needs to explore and understand the potentially critical role that aromatic molecules may play. The continued support of the Green Bank Telescope, as well as the upcoming JWST and planned ngVLA will be crucial to the observational success of this work.
McGuire,BrettNational Radio Astronomy ObservatoryClosing Gaps in Our Astrochemical Heritage: From Molecular Clouds to Planets
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We discuss the observational needs in the coming decade to enable the robust interpretation of chemical evolution from molecular clouds through to the formation of planets, especially in sources such as protoplanetary disks and exoplanet atmospheres, where only the simplest of species can be directly observed.
McGuire,BrettNational Radio Astronomy ObservatoryRevealing Chemical Evolution Throughout the Star-Formation Process
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We discuss the observational, modeling, and laboratory advances required to push our understanding of the evolution of the most complex, prebiotic chemistry in the ISM, including the potential cosmic origins of biological homochirality.
McIntosh,ScottNCAR/HAOInvestigating Coronal Magnetism with COSMO: Science on the Critical Path To Understanding The “Weather” of Stars and Stellarspheres
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The white paper discusses the measurement of coronal magnetism as a gateway to improving our understanding of the heliosphere, drive improvements in space weather and ultimately understanding stellar coronae and stellar weather.
McWilliams,SeanWest Virginia UniversityThe state of gravitational-wave astrophysics in 2020
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We will describe the scientific prospects for the field of gravitational-wave astronomy as a whole as we enter the coming decade, and we will place the specific contributions from a future space-based gravitational-wave observatory within this context.
Meeburg,Pieter DanielKavli Institute for Cosmology, Cambridge, UK, CB3 0HAPrimordial Non-Gaussianity
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The aim of this white paper is to motivate the search for primordial non-Gaussianities in cosmology. Non-Gaussianities provide a unique opportunity to explore physics at the highest energy scales. We highlight recent theoretical advances, which predict new forms of non-Gaussianity and identify promising observational avenues.
Meech,KarenInstitute for AstronomySampling Extrasolar Planetary Systems: Interstellar Objects in the Solar System
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Interstellar objects present a unique opportunity to sample material from another solar system. We need to be prepared for the next discoveries.
Megeath,TomUniversity of ToledoLow Mass Stars as Tracers of Star Formation in Diverse Environments
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Young low mass stars and protostars are tracers of star formation across the diverse natal environments found in our galaxy. Here we describe how surveys for young low mass stars and protostars can probe how environment influences the star formation rate, the IMF and the formation of bound clusters.
Meixner,MargaretSpace Telescope Science InstituteInfrared Stellar Populations: Probing the Beginning and the End
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The early and late stages of star formation and star death remain puzzles. Results from Spitzer and Herschel on the Magellanic Clouds demonstrated the power of infrared stellar populations. We need to do similar studies of galaxies in the local volume and go fainter in the Magellanic Clouds. JWST, and far-infrared observations will be needed.
Mennesson,BertrandJet Propulsion Laboratory, California Institute of TechnologyInterplanetary dust around main sequence stars: origin, magnitude, and implications for exoplanet habitability searches
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The brightness and spatial distribution of warm (≳200K) dust structures located within a few AU We motivate and identify here the main instrumental / observational advances required to gain further insights into the origins of exozodiacal dust clouds and better understand their impact on planetary habitability and habitability searches.
Metzger,BrianColumbia UniversityKilonovae: nUV/Optical/IR Counterparts of Neutron Star Binary Mergers with TSO
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UVOIR emission from binary NS mergers informs their nucleosynthesis and the properties of NSs. TSO is a Probe-class 1.3m telescope, with imaging/spectroscopy (R = 200, 1800) in 4 bands (0.3 - 5μm) and rapid slew capability to 90% of sky. TSO nUV-mid-IR spectra of LIGO-detected mergers will provide new constraints on NS structure/nucleosynthesis.
Meyer,EileenUniversity of Maryland Baltimore County (UMBC)Prospects for AGN Studies at Hard X-ray through MeV Energies
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This White Paper explores advances in the study of Active Galaxies (AGN) which will be enabled by new observing capabilities at MeV energies (hard X-rays to gamma-rays; 0.1−1000 MeV), with a focus on multi-wavelength synergies.
Michelson,PeterStanford UniversityMid-Frequency-Band Space Gravitational Wave Observations for the 2020 Decade
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The science case for the early development of a Mid-Frequency-Band gravitational waves observatory for the frequency band 10 mHz to 1 Hz, thus bridging between LIGO/VIRGO and the milli-hertz band of LISA- with usable sensitivity extending to 10 Hz.
Milam,StefanieNASA/GSFCEmerging Capabilities for Detection and Characterization of Near-Earth Objects (NEOs)
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Here we describe the status for the detection and characterization of Near-Earth Objects (NEO) with current and future observatories. A summary of the capabilities, limitations, and obtainable NEO parameters is provided.
Milisavljevic,DanPurdue UniversityAchieving Transformative Understanding of Extreme Stellar Explosions with ELT-enabled Late-time Spectroscopy
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We outline how late-time spectroscopic observations of supernovae made possible with the next generation of Extremely Large Telescopes will facilitate transformational science opportunities and rapidly accelerate the community towards our goal of achieving a complete understanding of supernova explosions.
Miller,JonUniversity of MichiganAccretion in Stellar-Mass Black Holes at High X-ray Spectral Resolution
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Accretion disks around stellar-mass black holes are optimal regimes in which to make observational tests of seminal theory that applies across the mass scale. High X-ray spectral resolution will enable the most incisive tests. This white paper briefly reviews the key ideas and examines three case studies.
Minchin,RobertUSRAInvisible Structures in the Local Universe
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Neutral hydrogen surveys have revealed the existence of dark and almost-dark structures around nearby galaxies and in local groups and clusters. Understanding these structures will give us insights into how hydrogen cycles in and out of galaxies in different environments and will help us to understand the occupancy of low-mass dark matter subhalos.
Mirocha,JordanMcGill UniversityFirst Stars and Black Holes at Cosmic Dawn with Redshifted 21-cm Observations
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Though difficult to detect directly, the first stars and black holes forming during the "cosmic dawn" can be constrained indirectly through the 21-cm background, which traces the properties of intergalactic hydrogen gas. In this white paper, we focus on the science enabled by low-frequency radio observations of the 10 < z < 30 epoch.
Monnier,JohnUniversity of MichiganImaging the Key Stages of Planet Formatio
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In this white paper, we explore how higher angular resolution beyond ALMA and 8m-class telescopes can extend our understanding of the key stages of planet formation, to resolve accreting circumplanetary disks themselves, and to watch planets forming in situ for the nearest star-forming regions.
Monnier,JohnUniversity of MichiganThe Future of Exoplanet Direct Detection
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Diffraction fundamentally limits our ability to image and characterize exoplanets. Interferometry offers some advantages in exoplanet detection and characterization and we explore in this white paper some of the potential scientific breakthroughs possible.
Moullet,ArielleUSRA/SOFIASolar System’s minor bodies: the role of the ngVLA
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Thermal observations of minor bodies in the Solar System , and in particular centimeter-wave measurements probing across the diurnal skin depth, are strongly indicative of fundamental properties of their surfaces. We describe how the sensitivity provided by the ngVLA is necessary to achieve thermal detections on a large number of small bodies.
Moustakas,LeonidasJPL/CaltechQuasar microlensing: Revolutionizing our understanding of quasar structure and dynamics
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Microlensing in strong-lens systems with quasars provides a unique detailed view of the internal structure of active black holes to the scale of nano-arcseconds. The case is made for the potential of this approach to revolutionize our understanding of quasar physics and its role in broader questions, with a coherent community strategy.
Mroczkowski,TonyEuropean Southern Observatory (ESO)A High-resolution SZ View of the Warm-Hot Universe
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We outline advances in the understanding of thermodynamic/kinematic properties of the warm-hot universe that can come through resolved measurements of the Sunyaev Zeldovich effects. Many advances will be enabled by new (sub)millimeter instrumentation on existing facilities, but truly transformative advances will require new mm/submm facilities.
Muirhead,PhilipBoston UniversitySearching for Exosatellites Orbiting L and T Dwarfs: Connecting Planet Formation to Moon Formation and Finding New Temperate Worlds
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L-type and T-type dwarfs span the boundaries between main-sequence stars, brown dwarfs, and planetary-mass objects. The discovery of satellites orbiting L or T dwarfs will have transformative implications. In this white paper, we discuss the scientific motivations behind searching for transiting satellites orbiting L and T dwarfs.
Mukherjee,ReshmiBarnard College, Columbia UniversityExploring Frontiers in Physics with Very-High-Energy Gamma Rays
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This white paper briefly summarizes what can be learned over the coming decade in studies of fundamental physics through ground-based gamma-ray observations over the 20 GeV to 300 TeV range. The superior sensitivity and energy coverage of next generation instruments such as CTA will allow unprecedented exploration of the frontiers of physics.
Murphy,EricNational Radio Astronomy ObservatoryUnsolved Problems in Modern Astrophysics: Anomalous Microwave Emission
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This white paper discusses potential ways to improve our understanding of anomalous microwave emission (AME), requiring new facilities. AME has remained a major foreground contaminant in CMB studies since first being discovered over 20 years ago, yet its physical origin remains an unsolved problem in modern astrophysics.
Murphy,EricNational radio Astronomy ObservatoryRobustly Mapping the Distribution of Star Formation in High-$z$ Galaxies
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This white paper discusses the scientific impact and importance for conducting resolved studies of star formation activity in large populations of galaxy disks during the epoch of peak galaxy assembly via free-free emission.
Murphy,EricNational Radio Astronomy ObservatoryTowards a Theory for Star Formation on All Scales
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This white paper focusses on resolved studies of star formation within large samples of nearby galaxies using diagnostics that are unbiased by dust, and can measure star formation activity over the full range of scales and galaxy environments that it operates.
Natarajan,PriyamvadaYale UniversityDisentangling nature from nurture: tracing the origin of seed black holes
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The origin of seed black holes is fiercely debated and is one of the key open questions in cosmology today. Gravitational wave events from supermassive binary black hole coalescences coupled with multi-messenger data can help disentangle initial seeding conditions from accretion and dynamics that modulate black hole growth over cosmic time.
Neiner,CoralieLESIA, Paris Observatory, FranceStellar physics with high-resolution UV spectropolarimetry
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Current burning issues in stellar physics, for both hot and cool stars, concern their magnetism and its impact on stellar structure, evolution, activity, and circumstellar environment. However, the role of magnetism is complex and thus poorly understood as of today. It needs to be quantified with high-resolution UV spectropolarimetric measurements.
Ness,MelissaColumbia/FlatironIn Pursuit of Galactic Archaeology
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The next decade affords tremendous opportunity to achieve the goals of Galactic archaeology. That is, to reconstruct the evolutionary narrative of the Milky Way, based on the empirical data that describes its current morphological, dynamical, temporal and chemical structures. Here, we describe the path to achieving this goal.
Neveu,MarcUniversity of Maryland, College Park / NASA Goddard Space Flight CenterInvestigating the Solar System’s Ocean Worlds with Next-Generation Space Telescopes
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The search for life on the solar system’s ocean worlds must involve space telescopes uniquely able to observe numerous distant targets at high spatial resolution, for nearly arbitrary amounts of time, unimpeded by the Earth’s atmosphere. Questions drawn from the NASA Roadmap to Ocean Worlds best addressed by telescopic measurements are presented.
Newman,AndrewCarnegie Institution for ScienceResolving Galaxy Formation at Cosmic Noon
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We describe opportunities to transform our view of galaxy evolution at Cosmic Noon (z~2) by spatially resolving both early galaxies and their surrounding gaseous media using the angular resolution and sensitivity uniquely afforded by extremely large telescopes.
Newman,JeffreyUniversity of Pittsburgh and PITT PACCDeep Multi-object Spectroscopy to Enhance Dark Energy Science from LSST
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This white paper describes the science opportunities to greatly improve measurements of cosmological parameters from LSST which would be made possible by community access to deep (i~25), highly-multiplexed OIR multi-object spectroscopy (MOS) on 8--40m telescopes. Companion papers discuss opportunities from wide-field MOS and single-object data.
Nisa,MehrUniversity of RochesterThe Sun at GeV--TeV Energies: A New Laboratory for Astroparticle Physics
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We discuss the unresolved puzzles in our understanding of the very-high-energy Sun from the standpoint of particle astrophysics, current and future observations of the Sun in gamma rays and neutrinos, and their significance for probing fundamental questions in cosmic-ray propagation, dark matter searches and multi-messenger astronomy.
Ntampaka,MichelleHarvard Data Science Initiative; Center for Astrophysics | Harvard & SmithsonianThe Role of Machine Learning in the Next Decade of Cosmology
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Machine learning (ML) methods have remarkably improved how cosmologists can interpret data. The next decade will bring new opportunities for data-driven discovery, but will also present new challenges for adopting ML methodologies. ML could transform our field, but it will require the community to promote interdisciplinary research endeavors.
Nyland,KristinaNRC, resident at NRLAGN Feedback Driven by Jet-ISM Interactions on Sub-Galactic Scales: Opportunities for Advancement in the Next Decade
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In this white paper, we describe how the unique capabilities of the next-generation Very Large Array will enable new advancements in our understanding of the impact of radio jet-ISM feedback on galaxy growth and evolution.
Oberg,KarinHarvard UniversityAstrochemical Origins of Planetary Systems
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White paper outlines the chemical processes that regulate and affect the outcome of planet formation, and makes recommendations on future observatories and laboratory and theory support needed to address outstanding questions.
Ojha,RoopeshUMBC/NASA GSFCNeutrinos, Cosmic Rays, and the MeV Band
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The Mev band holds the key to answering three astrophysical questions: the sites where cosmic Rays are produced and accelerated, the origins of high-energy neutrinos, and the physical mechanisms producing the high energy gamma-ray emission from blazars. Theoretical and experimental capabilities needed in the next decade are discussed.
Olsen,KnutNational Optical Astronomy ObservatoryScience Platforms for Resolved Stellar Populations in the Next Decade
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Large surveys of resolved stellar populations in the next decade will explore the nature of dark matter, unravel the star formation, chemical enrichment, and dynamical histories of the Milky Way and nearby galaxies, and probe fundamental physics. Data archives and Science Platforms will be critical to bringing their discoveries to fruition.
Oppenheimer,BenjaminUniversity of Colorado, BoulderImprint of Drivers of Galaxy Formation in the Circumgalactic Medium
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A sensitive X-ray telescope can bring about a revolution in observations of the CGM. Its hot component, now mostly undetected, will be richly mapped around normal galaxies. These observations, augmented by advances in the radio and a continued progress in the UV and mm-waves, will expose the missing pieces of our understanding of galaxy formation.
Orlando,ElenaKavli Institute for Particle Astrophysics and Cosmology and Hansen Experimental Physics Laboratory, Stanford UniversityCosmic Rays and interstellar medium with Gamma-Ray Observations at MeV Energies
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We discuss the scientific prospects for studying cosmic rays and interstellar medium by observing gamma rays at MeV with unprecedented sensitivity and resolution. Low-energy cosmic rays and their sources, spectra all over the Galaxy, abundances, transport properties, and their role on the Galaxy evolution and star formation will be accessed.
Orlowski-Scherer,JohnUniversity of PennsylvaniaCharacterizing Extra-solar Oort Clouds withSubmillimeter-wave Observations
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In the paper we present motivation for the search for Extra-solar Oort clouds, and consider the prospects for their detection with current and upcoming experiments.
Osten,RachelSpace Telescope Science Institute, Johns Hopkins UniversityStellar X-ray Spectroscopy Addresses Fundamental Physics of Stellar Coronae, Accretion, and Winds, and Informs Stellar and Planetary Studies
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This white paper motivates open questions in stellar magnetic activity which X-ray spectroscopy can uniquely address. The answers to these questions are important for stellar astrophysics, but also have implications for exoplanet habitability as well.
Osten,RachelSpace Telescope Science Institute, Johns Hopkins UniversityAdvancing Understanding of Star-Planet Ecosystems in the Next Decade: The Radio Wavelength Perspective
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In this white paper we advocate for stellar radio observations as a way to advance understanding of stars in service of a better understanding of star-planet ecosystems. Specific key advances needed are sensitivity and access to a broader range of frequency space to make progress in understanding the space weather environments of exoplanets.
Overzier,RoderikObservatório Nacional / Institute of Astronomy, Geophysics and Atmospheric Sciences, University of São PauloTracing the formation history of galaxy clusters into the epoch of reionization
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Protoclusters at z>2 are the sites of cluster formation. Deep, wide surveys are now delivering large numbers of these structures, allowing us to trace the origin of galaxy clusters into the epoch of reionization. Here we review our current understanding of the field with an emphasis on the next generation of large aperture telescopes.
Pacucci,FabioKapteyn Astronomical Institute, Yale UniversityDetecting the Birth of Supermassive Black Holes Formed from Heavy Seeds
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We investigate the capabilities required to study supermassive black holes formed by heavy seeds in the early Universe. We show that detecting heavy seeds at z>10 in the next decade will be feasible with upcoming and/or proposed facilities. Their detection will be fundamental to understand the early history of the Universe and its evolution.
Paladini,RobertaCaltech-IPACOn the Origins of the Initial Mass Function
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In order to establish if the IMF and CMF are Universal, it is necessary to: 1) perform multi-wavelength large-scale imaging and spectroscopic surveys; 2) require an angular resolution of <0:1" in the optical/near-IR and <5"in the far-IR; 3) achieve far-IR sensitivities to probe 0.1 M cores at 2–3 kpc.
Palmese,AntonellaFermi National Accelerator LaboratoryGravitational wave cosmology and astrophysics with large spectroscopic galaxy surveys
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During the next decade, measurements of the Hubble constant from gravitational wave standard sirens will potentially reach a 1-2% uncertainty. The next generation of spectroscopic galaxy surveys will play a crucial role towards achieving such precision, and towards improving our understanding of gravitational wave sources.
Papovich,CaseyTexas A&M UniversityUV Diagnostics of Galaxies from the Peak of Star-Formation to the Epoch of Reionization
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We describe prospects facilitated by giant telescopes in the 2020s to use rest-frame UV spectroscopy to study the properties of massive stellar populations and gas (ionization, metallicity, kinematics, outflows) in and around galaxies from the peak of the cosmic star-formation density (z~3) up in to the epoch of reionization (z>6).
Pasham,DheerajMassachusetts Institute of TechnologyProbing the Cosmological Evolution of Super-massive Black Holes using Tidal Disruption Flares
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X-ray spectral-timing studies of tidal disruption events to build a census of supermassive black hole spins at various redshifts and study super-Eddington accretion around supermassive black holes in the local Universe to understand how they may have grown at high redshifts.
Peeples,MollySpace Telescope Science Institute / Johns Hopkins UniversityUnderstanding the circumgalactic medium is critical for understanding galaxy evolution
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The circumgalactic medium is a major reservoir of baryons and metals, playing a key role in the long cycles of accretion, feedback, and recycling of gas driving galaxy evolution. Fundamental progress on major issues in galaxy evolution depends critically on improved empirical characterization and theoretical understanding of circumgalactic gas.
Pellegrini,EricUniversity of HeidelbergMaking the Connection between Feedback and Spatially Resolved Emission Line Diagnostics
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We argue that crucial progress in the coming decade will depend on the ability to obtain spatially resolved spectroscopic observations of HII regions for reliable instantaneous measurements of their physical conditions, with full galactic coverage to obtain a population sample with line sensitivities significantly deeper than past efforts.
Penny,MatthewThe Ohio State UniversityMeasurement of the Free-Floating Planet Mass Function with Simultaneous Euclid and WFIRST Microlensing Parallax Observations
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Free-floating planets (FFPs) are the remnants of violent dynamical rearrangements of planetary systems. This white paper describes how the mass function of FFPs can be measured by combining WFIRST and Euclid microlensing observations, which WFIRST cannot do alone.
Perez,KerstinMassachusetts Institute of TechnologyCosmic-ray Antinuclei as Messengers for Dark Matter
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Low-energy antideuterons provide a “smoking gun” signature of dark matter annihilation or decay, essentially free of astrophysical background. Low-energy antiprotons are a vital partner for this analysis, and low-energy antihelium could provide further discovery space for new physics.
Perlman,EricFlorida Institute of TechnologyRelativistic Jets in the Accretion & Collimation Zone : New Challenges Enabled by New Instruments
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We point out advances that can be achieved by new technology in the zone where AGN jets are accelerated to relativistic speeds and collimated. The ngVLA, near-IR, near-IR, optical and X-ray interferometry, and other projects can produce fundamental advances in understanding jet production, acceleration, collimation and high-energy phenomena.
Perlman,EricFlorida Institute of TechnologyKiloparsec-scale Jets: Physics, Emission Mechanisms, and Challenges
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AGN Jets transport material and energy from sub-pc central regions out beyond their host galaxies. Many issues remain for kpc-scale jets, from dynamics and their interaction with surrounding media to particle acceleration and high-energy emission mechanism. We concentrate on the advances that can be made by new missions and technologies.
Perlmutter,SaulUC Berkeley / LBNLThe Key Role of Supernova Spectrophotometry in the Next-Decade Dark Energy Science Program
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For LSST and WFIRST to together take a major step forward in the SN measurements of dark energy the leading systematics --SN population drift and changes in dust properties-- both must be constrained. This requires space-based instrumentation to provide the wide-wavelength-range spectrophotometry, not just imaging, to measure these two effects.
Petric,AndreeaInstitute for AstronomyHigh Redshift Obscured Quasars and the Need for Optical to NIR, Massively Multiplexed, Spectroscopic Facilities
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We emphasize the need for future massively multiplexed spectroscopic instruments that can perform dedicated surveys in the optical and NIR to pin down the nature and demographics of obscured growing black-holes at z>1. These key studies will shed light on the role of black holes in galaxy evolution during the epoch of peak growth activity.
PEVTSOV,ALEXEINATIONAL SOLAR OBSERVATORYHistorical astronomical data: urgent need for preservation, digitization enabling scientific exploration
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This white paper emphasizes critical importance of preservation, digitization and scientific exploration of historical astronomical data. It outlines the rationale, provides examples of new science with such data, and reviews the potential losses to science if nothing it done.
Pierce,MichaelUniversity of WyomingTransverse Extragalactic Motions: a New Method for Constraining Cosmological Parameters
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The geometrical nature of strong lensing can provide cosmological constraints that are independent of the traditional methods. Specifically, multiple-arc systems where a single lens images multiple background objects and via a new method based on cosmological parallax from the Galaxy's motion with respect to the Cosmic Microwave Background.
Pierce,MichaelUniversity of WyomingCharacterizing the Assembly of Galaxy Cluster Populations Over Cosmic time
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The coming ELTs promise to revolutionize our understanding of the assembly and evolution of galaxies near the epoch of peak assembly (z ~ 2). However, complementary data sets for lower redshift populations will be be necessary to fully complement the ELT surveys. An extensive, survey of the elliptical populations in 1 < z clusters is advocated.
Pineda,Jorge L.Jet Propulsion Laboratory, California Institute of TechnologyProbing Galaxy Evolution through Far- Infrared Spectroscopy of the Interstellar Medium.
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In this white paper we lay out a roadmap that builds on the use of multi-scale, high-spectral resolution observations of far-infrared fine-structure lines, to study the physical processes governing the evolution of the interstellar medium in galaxies, and how they impact the regulation of star formation in galaxies.
Pisani,AlicePrinceton UniversityCosmic voids: a novel probe to shed light on our Universe
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In this paper we present the case for void science, arguing that cosmic voids are a novel probe to constrain modified gravity, dark energy, the sum of neutrino masses and galaxy evolution. Voids will answer some of the most relevant questions in cosmology and astrophysics over the next decade.
Pisano,D.J.West Virginia UniversityCompleting the Hydrogen Census in the Circumgalactic Medium at z~0
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A description of the contributions of 21cm emission observations with single-dish telescopes to understanding the CGM of galaxies and accretion processes. Supporting interferometric UV absorption line observations are also discussed.
Plavchan,PeterGeorge Mason UniversityCommunity Endorsement of the National Academies Exoplanet Science Strategy and Astrobiology Strategy for the Search for Life in the Universe Reports
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The National Academies “Exoplanet Science Strategy” and “Astrobiology Strategy for the Search for Life in the Universe” reports present timely and consensus assessments of the priorities and recommendations of our science communities. We are signing our support for their findings and recommendations as input to the Astrophysics 2020 decadal survey.
Plotkin,RichardUniversity of Nevada, RenoLocal Constraints on Supermassive Black Hole Seeds
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This white paper discusses how proposed multiwavelength facilities going into the 2020s/2030s will allow us to assemble large samples of weakly accreting active galactic nuclei in low-mass galaxies, in order to constrain the mass-distribution of objects that originally seeded the growth of supermassive black holes.
Pontoppidan,KlausSpace Telescope Science InstituteThe trail of water and the delivery of volatiles to habitable planets
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Water is fundamental to our understanding of the formation of planets and the delivery of volatiles to their surfaces. Yet, we currently have no facilities capable of comprehensively observing it. A cold, space-based observatory operating at 25-600 micron is needed to address fundamental questions about the origin of planets and their water.
Pooley,DavidTrinity UniversityThe Most Powerful Lenses in the Universe: Quasar Microlensing as a Probe of the Lensing Galaxy
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We describe how quasar microlensing is the only way to determine the dark/stellar ratio at the interesting sub-galactic scales of several kpc and how it is the only way to measure the stellar M/L outside the solar neighborhood. Both can be done as a function of redshift, and this requires sub-arcsecond X-ray imaging of LSST-discovered lenses.
Pope,AlexandraUniversity of Massachusetts AmherstSimultaneous Measurements of Star Formation and Supermassive Black Hole Growth in Galaxies
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Quantifying the relative growth of stars and black holes in galaxies over cosmic time and along the cosmic web using thermal infrared and interferometric radio observations
Price,SaraHarvard-Smithsonian Center for AstrophysicsPicturing a Panchromatic Past and Future
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This white paper sets forth a few examples of impressive multi-wavelength discoveries by the Great Observatories, taken from a comprehensive analysis of Chandra press and image releases, in order to argue for a similar panchromatic approach in planning for future missions.
Price-Whelan,AdrianPrinceton UniversityStellar multiplicity: an interdisciplinary nexus
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This white paper emphasizes the interdisciplinary importance of binary-star science and advocates that coordinated investment in understanding stellar multiplicity from all astrophysical communities will benefit almost all branches of astrophysics.
Rackham,BenjaminUniversity of ArizonaConstraining Stellar Photospheres as an Essential Step for Transmission Spectroscopy of Small Exoplanets
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Transmission spectra probe the atmospheres of transiting exoplanets, but these observations are also subject to signals introduced by magnetic active regions on host stars. We outline scientific opportunities in the next decade for providing useful constraints on stellar photospheres for the purposes of exoplanet transmission spectroscopy.
Rahmani,HadiParis ObservatoryQuasar absorption lines as astrophysical probes of fundamental physics and cosmology
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Quasar absorption lines provide unique tools to probe fundamental physics over cosmological scales. In this WP, we discuss the current open questions in the modern cosmology that can be answered, uniquely, using such absorption lines. We emphasise the essential role of a future high spectral resolution UV spectrograph in space, like LUVOIR/POLLUX.
Ramirez,RamsesEarth-Life Science Institute (ELSI), Tokyo Institute of TechnologyHabitable zone predictions and how to test them
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The classical HZ definition makes a number of assumptions common to the Earth. We discuss these and the observations needed to test them. We also discuss how next-generation missions are only the beginning of a much more data-filled era in the near future, allowing us to actually determine which planets are most likely to exhibit life.
Rani,BinduNASA Goddard Space Flight Center, USAMulti-Physics of AGN Jets in the Multi-Messenger Era
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This new era of multi-messenger astronomy, which will mature in the next decade, offers us the unprecedented opportunity to combine more than one messenger to solve some long-standing puzzles of AGN jet physics. We advocate the support to future instruments with large effective areas, excellent timing resolution, and wide fields of view.
Rani,BinduNASA Goddard Space Flight Center, USAHigh-Energy Polarimetry - a new window to probe extreme physics in AGN jets
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We discuss the scientific potentials of gamma-ray polarimetry including the theoretical implications, and observational technology advances being made. We explore the primary scientific opportunities and wealth of information expected from synergy of multi-wavelength polarimetry that will be brought to multi-messenger astronomy.
Rankin,JoannaUniversity of VermontA Plasma-Physical Understanding of Pulsar Radio Emission Physics
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The paper treats the longstanding problem of understanding pulsar radiation physically. It reports on progress in understanding both the radio and thermal X-ray emission, observationally and theoretically. It argues that recent progress has placed the emission problem on a plasma physics basis and that new efforts will have broad consequences.
Rau,GioiaNASA/GSFC & CUACool, evolved stars: results, challenges, and promises for the next decade
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This White Paper identifies compelling scientific opportunities in the field of Cool, Evolved Stars, describing the observational and theorical challenges to our understanding, and the key advancements made. We portray the pathway towards understanding, and identify, through recommendations, which advancements are necessary in 2020-2030 & beyond.
Ravi,VikramCenter for Astrophysics | Harvard & Smithsonian; CaltechFast Radio Burst Tomography of the Unseen Universe
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The discovery of Fast Radio Bursts (FRBs) at cosmological distances has opened a powerful window on otherwise unseen matter in the Universe. Observations of >10^4 FRBs will assess the baryon contents and physical conditions in the hot/diffuse circumgalactic, intracluster, and intergalactic medium, and test extant compact-object dark matter models.
Ravindranath,SwaraSpace Telescope Science InstituteSpatially-resolved studies of star-forming galaxies in the reionization epoch
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Spatially-resolved emission line studies of reionization sources probing few 10-100s parsecs is key to understanding the earliest phases of galaxy assembly, growth of seed black holes, and formation of proto-globular cluster. High spatial resolution (<100 mas), high spectral resolution (R>4000), and high sensitivity are necessary to make progress.
Rayner,JohnIRTF/University of HawaiiAstrophysics with the NASA Infrared Telescope Facility
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Much frontline astronomical research can still be done on 3-4-m class optical-infrared telescopes. This paper highlights future key observing that can be efficiently done on IRTF by exploiting current and planned capabilities.
Reach,WilliamUSRAFar-Infrared studies of Galaxy Evolution
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Far-infrared observations trace galaxy evolution through dust thermal emission, including its polarization, and fine-structure lines from the gas. Galaxy evolution must be informed by properties of galaxies that can be resolved and physical mechanisms (heating, cooling, and magnetic field influence) witnessed.
Reid,MarkCenter for Astrophysics | Harvard & SmithsonianScience Opportunities with Long Baseline Radio Interferometry and Micro-arcsecond Astrometry
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Long Baseline Radio Interferometry can achieve the highest angular resolution in astronomy and has demostrated astrometric accuracy of ~10 microarcseconds. With increased sensitivity it can achieve ~1 microarcsecond accuracy, uniquely opening a wide range of astrophysical problems for study.
Reinhard,ChristopherGeorgia Institute of TechnologyThe remote detectability of Earth's biosphere through time and the importance of UV capability for characterizing habitable exoplanets
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Using Earth system evolution as a guide, we suggest that near-term volume-limited surveys of habitable zone planets orbiting nearby Sun-like stars is best accomplished with a combined UV-optical-NIR sensitive surveyor.
Reitze,DavidCalifornia Institute of TechnologyThe US Program in Ground-Based Gravitational Wave Science: Contribution from the LIGO Laboratory
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This white paper presents a synopsis of the scientific opportunities afforded by Cosmic Explorer, a gravitational-wave observatory for the 2030s, and presents an overview of the technical developments needed in the 2020s to enable their construction.
Remijan,AnthonyNational Radio Astronomy ObservatoryOBSERVATIONAL ASTROCHEMISTRY IN THE NEXT DECADE
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In order to continue to make progress in how the chemical and physical nature of molecular material changes as we move from the diffuse interstellar medium to compact cores and eventually disks with planetary systems, as a community, we need observations of large astronomical molecules over large spatial scales and bandwidths.
Reynolds,ChristopherUniversity of CambridgeHigh-Energy Astrophysics in the 2020s and Beyond
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This White Paper illustrates the central role of high-energy astrophysics to some of the most pressing astrophysical problems of our time, the formation/evolution of galaxies, the origin of the heavy elements, star and planet formation, the emergence of life on exoplanets, and the search for new physics.
Rho,JeongheeSETI InstituteAre Supernovae the Dust Producer in the Early Universe?
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The large quantities of dust in high-redshift galaxies raise a fundamental question as to the origin of dust in the early Universe. Supernovae occur within several millions of years. This white paper will focus on dust formation in SN ejecta with US-Extremely Large Telescope (ELT) perspective during the era of JWST and LSST.
Rhodes,JasonJet Propulsion Laboratory, California Institute of TechnologyThe End of Galaxy Surveys
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We advocate for defining a path to end the era of galaxy surveys by making the definitive measurements of the galaxy population in the optical/NIR, thereby creating a map of galaxies (and their associated dark matter) throughout the entire visible universe.
Rhodes,JasonJet Propulsion Laboratory, California Institute of TechnologyCosmological Synergies Enabled by Joint Analysis of Multi-probe data from WFIRST, Euclid, and LSST
.pdf
WFIRST, Euclid, and LSST are all missions designed to perform dedicated cosmology surveys that offer unprecedented statistical constraining power and control of systematic uncertainties. There is a growing realization that these missions will be significantly more powerful when the data are processed and analyzed in unison.
Rich,R. MichaelDepartment of Physics and Astronomy, UCLAThe Chemical/Dynamical Evolution of the Galactic Bulge
.pdf
This paper points out several current problems in the study of the Galactic bulge, such as the age and structure problems, and advocates high resolution, high S/N, optical spectroscopy of the bulge as enabled by facilities being planned in the next decade.
Ridgway,StephenNOAOPrecision Analysis of Evolved Stars
.pdf
The broad recommendation of this paper is three-fold: recognize the essential role of stellar physics in all of astronomy and cosmology; note that a revolution in stellar measurement capabilities, datasets, and modeling is underway and gaining momentum; and support the scientists, their essential technologies and observatories.
Rieke,GeorgeUniversity of ArizonaJWST/MIRI Surveys in GOODS-S
.pdf
JWST/MIRI GTO programs in GOODS-S will (1) measure obscured star formation rates down to 10 Mʘ/yr; (2) measure aromatic band strengths to constrain processes in galaxy ISMs; (3) complete our inventory of AGN types; (4) improve mass estimates for galaxies at z > 4; and (5) help determine masses and ages of young stellar populations at z > 8.
Rieke,MarciaUniversity of ArizonaJWST GTO/ERS Deep Surveys
.pdf
Discovering and characterizing the first galaxies to form in the early Universe is one of the prime reasons for building a large, cold telescope in space, JWST. This white paper describes an integrated GTO program using 800 hours of prime time and 800 hours of parallel time to study the formation and evolution of galaxies from z ~2 to z~14.
Rigby,JaneNASA Goddard Space Flight CenterThe production and escape of ionizing photons from galaxies over cosmic time
.pdf
Ionizing photons produced by massive stars play a key role in galaxy evolution and in ending the dark ages. Fundamental unsolved questions about the production and escape of ionizing photons, and how ionizing galaxy populations evolve through cosmic time, can be definitively answered with next-gen UV spectroscopy, in concert with JWST and the ELTs.
Rix,Hans-WalterMax Planck Institute for Astronomy, HeidelbergBinaries Matter Everywhere: from Precision Calibrations to Re-Ionization and Gravitational Waves
.pdf
Binary stars are pivotal for the coming decade, enabling our understanding of star-formation, stellar evolution, stellar death, supernovae, black hole formation, cosmic re-ionization, and gravitational wave events. The field needs time-domain surveys in photometry, astrometry and spectroscopy. The first two exist, the last not (yet)!
Robertson,BrantUC Santa Cruz and Institute for Advanced StudyUnderstanding Galaxy Formation via Near-Infrared Surveys in the 2020s
.pdf
A discussion of science cases in extragalactic astrophysics and galaxy formation that wide-area space-based infrared surveys will address in the 2020s.
Robinson,TylerNorthern Arizona UniversityCharacterizing Exoplanet Habitability
.pdf
Characterizing habitable exoplanets is a critical, aspirational goal for astronomy and astrophysics. We discuss a range of habitability indicators and their associated observing requirements. These requirements highlight next generation space telescopes as the key to studying habitable environments outside the Solar System.
Roederer,IanUniversity of MichiganThe Potential of Ultraviolet Spectroscopy to Open New Frontiers to Study the First Stars
.pdf
The elements found in second-generation stars probe the nature and end states of the elusive generation of metal-free first stars. High-resolution (R ≥ 30,000) ultraviolet (~1800-3100 Å) spectroscopy offers the potential to greatly expand the chemical inventory in second-generation stars. Facilities like CETUS, HabEx, and LUVOIR meet these goals.
Roederer,IanUniversity of MichiganThe astrophysical r-process and the origin of the heaviest elements
.pdf
The r-process is responsible for production of the heaviest elements, but many open questions remain about its nature. To answer these questions requires meaningful public access to high-resolution, UV/blue/optical spectroscopic instruments on 6-10 m telescopes, 30 m ELTs, and the next generation of space UV facilities.
Roederer,IanUniversity of MichiganThe First Stars and the Origin of the Elements
.pdf
No metal-free "first stars" have yet been found. We describe a survey strategy that could find one or more such stars or exclude their existence at reasonable confidence. This survey would leverage unique aspects of a two-hemisphere US-ELT system to characterize the nature of the elusive generation of first stars.
Roettenbacher,RachaelYale UniversityHigh Angular Resolution Astrophysics: Resolving Stellar Surface Features
.pdf
We discuss the main types of stars for which imaging surface features is currently possible using long-baseline optical interferometry and what improved observing techniques would provide for imaging stellar surface features.
Roman-Duval,JuliaSpace Telescope Science InstituteMetal Abundances and Depletions in the Neutral Interstellar Medium of Galaxies: the Local Volume as a Laboratory
.pdf
Multi-object UV-optical spectroscopy toward massive stars within 15 Mpc covering a wide range of metallicities and morphological types will provide the abundance measurements needed to characterize the lifecycle of metals in neutral gas and dust in galaxies, thereby addressing important questions about chemical enrichment.
Ross,NicholasUniversity of EdinburghOpportunities in Time-Domain Extragalactic Astrophysics with the NASA Near-Earth Object Camera (NEOCam)
.pdf
This White Paper motivates the time domain extragalactic science case for the NASA Near-Earth Object Camera (NEOCam). Using the NEOWISE-R model, for relatively little cost, additional NEOCam data processing will have a massive scientific and legacy impact on extragalactic science, especially in the nascent field of AGN IR variability studies.
Rudie,Gwen C.Carnegie Institution for ScienceObserving Galaxies and Dissecting their Baryon Cycle at Cosmic Noon
.pdf
We describe new observations possible with wide-field spectroscopy on an ELT that can transform our understanding of galactic winds and the baryon cycle and their effect on galaxy evolution at z~2-3.
Ruszkowski,MateuszUniversity of Michigan in Ann ArborSupermassive Black Hole Feedback
.pdf
Galaxy evolution is critically shaped by the energy injection from supermassive black holes (SMBHs). A major challenge is unraveling how the energy released near the SMBHs is distributed throughout galaxies and their environments. This white paper discusses the prospect of tackling this problem using high-resolution X-ray/microwave observations.
Ryan,RussellSpace Telescope Science InstituteThe WFIRST Deep Grism Survey: WDGS
.pdf
We present several science questions that require a deep grism program with the Wide-Field Infrared Survey Telescope.
Rymer,AbigailJHUAPLSolar System Ice Giants: Exoplanets in our Backyard.
.pdf
Future exoplanet exploration can be enhanced by solar system exploration, here we focus on how analysis of solar system Ice Giants can provide enhanced science return to astrophysical measurements and solicit inclusion of specific wording supporting the astrophysical significance of an Ice Giant flagship-class mission in the Astro2020 report.
Sadavoy,SarahHarvard-Smithsonian Center for AstrophysicsThe Life Cycle of Dust
.pdf
White paper describes efforts to improve our understanding of the life cycle of dust. Paper highlights the need for multi-wavelength spectroscopy and continuum observations to study the main sources of dust production and how grain compositions and grain sizes change locally and across cosmic time.
Safi-Harb,SamarUniversity of ManitobaHigh-Resolution X-ray Imaging Studies of Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants
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Supernova remnants and neutron stars serve as nearby laboratories relevant to many areas in Astrophysics. In this white paper, we highlight some science breakthroughs to be achieved with future X-ray missions (such as the proposed AXIS probe) equipped with sub-arcsecond imaging resolution and an order of magnitude improvement in sensitivity.
Sahai,RaghvendraJet Propulsion Laboratory, California Institute of TechnologyProbing Strong Binary Interactions and Accretion in Asymptotic Giant Branch Stars
.pdf
Understanding strong binary interactions is of wide astrophysical importance, and the deaths of most stars in the Universe that evolve in a Hubble time (~1-8 Msun) could be fundamentally affected by such interactions. We outline the main scientific issues and how these can be addressed with upcoming facilities in the radio, UV and X-ray domains.
Sallum,StephUniversity of California, Santa CruzImaging Giant Protoplanets with the ELTs
.pdf
Constraining the details of giant planet formation requires building a census of forming planets and characterizing protoplanetary disks. This whitepaper describes the scientific progress in observational planet formation studies that will be made possible by instrumentation advances during the next decade.
Salter,ChristopherGreen Bank ObservatoryRadio Scintillation Studies of Comet Ion Tails
.pdf
Future studies of comet ion tails using scintillation observations of the compact radio sources that they occult.
Salter,ChristopherGreen Bank Observatory & Arecibo ObservatorySecular Transient Radio Sources
.pdf
The discovery and study of "secular transient radio sources" are reviewed via a number of examples. The continuing major contributions by large single-dish radio telescopes to the discovery, monitoring and VLBI follow-up studies of these transients are highlighted.
Sanderson,RobynUniversity of Pennsylvania / Flatiron InstituteThe Multidimensional Milky Way
.pdf
In the next decade our understanding of the Milky Way's dynamics, stellar populations, and structure will be revolutionized, thanks to proposed astrometric, spectroscopic and photometric surveys. We describe the new science this multidimensional view will enable across astrophysics, from constraints on dark matter to insights into galaxy formation.
Santander,MarcosUniversity of AlabamaA Unique Messenger to Probe Active Galactic Nuclei: High-Energy Neutrinos
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We advocate for a multi-messenger approach that combines high-energy neutrino and broad multi-wavelength electromagnetic observations to study AGN during the coming decade. The unique capabilities of these joint observations promise to solve several long-standing issues in our understanding of AGN as powerful cosmic accelerators.
Sarazin,FredColorado School of MinesWhat is the nature and origin of the highest-energy particles in the universe?
.pdf
This white paper defines the science questions to be answered in the next decade in the field of Ultra-High Energy Cosmic-Rays. Following a review of the recent experimental and theoretical advances in the field, the paper outlines strategies and requirements desirable for the design of future experiments.
Sathnur,AshwiniUnited Nations Development ProgrammeSolar flares and Quantum Neural Networks
.pdf
Introduction of new technologies on the conceptual ideologies of Accessibility. This white paper describes the innovative themes of solar flares and the realization of implementation of new technologies. The human astronauts end users are located in the space regions where there could be incidents of exposure to the solar flares and the radiation.
Sathyaprakash,BangaloreThe Pennsylvania State UniversityCOSMOLOGY AND THE EARLY UNIVERSE
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This WP deals with what we might learn from future gravitational wave observations about the early universe phase transitions and their energy scales, primordial black holes, Hubble parameter, dark matter and dark energy, modified theories of gravity and extra dimensions.
Sathyaprakash,BangaloreThe Pennsylvania State UniversityEXTREME GRAVITY AND FUNDAMENTAL PHYSICS
.pdf
Future gravitational-wave observations will enable unprecedented and unique science in extreme gravity and fundamental physics answering questions about the nature of dynamical spacetimes, the nature of dark matter and the nature of compact objects.
Sathyaprakash,BangaloreThe Pennsylvania State UniversityMULTIMESSENGER UNIVERSE
with GRAVITATIONAL WAVES from BINARY SYSTEMS
.pdf
Future GW detector networks and EM observatories will provide a unique opportunity to observe the most luminous events in the Universe involving matter in extreme environs. They will address some of the key questions in physics and astronomy: formation and evolution of compact binaries, sites of formation of heavy elements and the physics of jets.
Savin,Daniel WolfColumbia UniversityAstrophysical Science enabled by Laboratory Astrophysics Studies in Atomic, Molecular, and Optical (AMO) Physics
.pdf
We highlight a few of the many astrophysical advances that will become possible with advances in AMO laboratory astrophysics. This submission supersedes the previous submission.
Schaefer,GailThe CHARA Array of Georgia State UniversityBinary and Multiple Star Systems at High Angular Resolution
.pdf
Binary and multiple star systems provide laboratories for measuring stellar masses and studying star formation, stellar evolution, and dynamical evolution over time. This paper outlines several areas in the context of binary stars that can be advanced over the next decade.
Schaefer,GailThe CHARA Array of Georgia State UniversityHigh Angular Resolution Astrophysics in the Era of Time Domain Surveys
.pdf
Over the next decade, all-sky photometric surveys will dramatically increase the number of time variable objects discovered. Long-baseline optical interferometry has the power to resolve the spatial structure of bright transients like the early stages of novae explosions, Be star outbursts, and gravitational microlensing.
Schroeder,FrankBartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE, USAHigh-Energy Galactic Cosmic Rays
.pdf
The origin of the highest energy Galactic cosmic rays is still not understood, nor is the transition to EeV extragalactic particles. Scientific progress requires enhancements of existing air-shower arrays, such as: IceCube with its surface detector IceTop, and the low-energy extensions of both the Telescope Array and the Pierre Auger Observatory.
Schussler,FabianIRFU, CEA Paris-SaclayAll-Sky time domain astrophysics with Very High Energy Gamma rays
.pdf
Transient astronomy has witnessed a remarkable evolution with recent discoveries across all astrophysical messengers. We here discuss present key examples of transient sources which would be prime targets for wide field-of-view ground-based observatories observing in the very-high-energy gamma-ray domain.
Scolnic,DanielDuke UniversityThe Next Generation of Cosmological Measurements with Type Ia Supernovae
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The next era promises to be extremely exciting in the number of different ways SNe Ia are used to measure various cosmological parameters. Here we review the experiments in the 2020s that will yield orders of magnitudes more SNe Ia and we discuss five different cosmological probes with SNe Ia.
Scowen,PaulArizona State UniversityOutline of Analysis Studies Conducted by NASA Cosmic Origins Program Analysis Group Members During the Past 10 Years
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We outline several analysis studies that have been conducted by the NASA COPAG since the Astro2010 Decadal Survey was performed. The studies are intentionally free of advocacy and lay out the current state of the discipline in each case. We provide the information so that it may be of use to the Committee in their deliberations.
Sehgal,NeelimaStony Brook UniversityScience from an Ultra-Deep, High-Resolution Millimeter-Wave Survey
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Opening up a new window of millimeter-wave observations that span frequency bands in the range of 30 to 500 GHz, survey half the sky, and are both an order of magnitude deeper and of higher-resolution than currently funded surveys would yield an enormous gain in understanding of both fundamental physics and astrophysics.
Sembach,KenSpace Telescope Science InstituteThe Search for Life Elsewhere as a Compelling Science Theme for Astro2020
.pdf
We review the evolving science drivers underpinning the search for life elsewhere, as articulated in our own decadal surveys in years past. We also review other documents, and provide a brief digression that considers a philosophy of addressing cost. Our hope is to set the stage for concluding the initial phase of the search for life.
Shandera,SarahThe Pennsylvania State UniversityProbing the origin of our Universe through cosmic microwave background constraints on gravitational waves
.pdf
We lay out the impact of the next generation of CMB polarization measurements on our understanding of high energy particle physics, gravity, and the origin of the Universe.
Shao,MichaelJet Propulsion Laboratory, California Institute of TechnologyFinding Exo-Earths with Precision Space Astrometry
.pdf
Astrometry may be the only technique capable of finding Earth-twins. It measures the reflex motion of a star in the plane of the sky allowing one to determine a planet’s mass and its orbital inclination. Astrometric measurements with 1 uas precision allow to search for a 1 M_earth planet in the middle of the habitable zone.
Shawhan,PeterUniversity of Maryland and Joint Space-Science InstituteMulti-Messenger Astrophysics Opportunities with Stellar-Mass Binary Black Hole Mergers
.pdf
It is often thought that stellar-mass binary black hole mergers should not produce a detectable electromagnetic transient. However, there ARE a number of mechanisms for producing such a counterpart. We review these, and the astrophysics and fundamental physics we can learn from detecting or constraining them.
Sheehan,PatrickNational Radio Astronomy ObservatoryProtostellar Disks: The Missing Link Between Cores and Planets
.pdf
A look at the studies and facilities needed to move forward our understanding of protostellar disks, which represent the initial conditions in disks after forming from cloud collapse but before planet formation has occurred.
sheikh,davidZeCoat CorporationMethod to aluminum-coat telescope mirrors in space for EUV-broadband astronomy
.pdf
Telescope mirrors and gratings coated on-orbit with bare aluminum may allow broadband observations that include the EUV band between 30-nm and 100-nm and would have broadband coverage from the EUV through the long IR. High-discharge lithium battery technology exists today to build a large, self-coating telescope in space.
Shen,YueUniversity of IllinoisMapping the Inner Structure of Quasars with Time-Domain Spectroscopy
.pdf
This White Paper discusses the needs to understand the accretion processes of quasars and to measure their fundamental physical properties using time-domain spectroscopy, and opportunities from future surveys and facilities in the upcoming landscape of time-domain astrophysics.
Shoemaker,DavidMITGravitational-Wave Astronomy in the 2020s and Beyond: A view across the gravitational wave spectrum
.pdf
We present a broad outline of the scientific impact of Gravitational-wave detector facilities in the coming decade and the 2030s, emphasizing the ways in which they complement one another as well as other, more traditional astronomical resources.
Shoemaker,DavidMassachusetts Institute of TechnologyGravitational wave astronomy with LIGO and similar detectors in the next decade
.pdf
We describe the plans for gravitational-wave observations and astrophysics that will be carried out in the next decade using data from the LIGO Observatories in the US and sister facilities abroad. We provide an overview of gravitational wave signal types that we are targeting, and the role of gravitational waves in multi-messenger astronomy.
Siemens,XavierUniversity of Wisconsin -- MilwaukeePhysics Beyond the Standard Model With Pulsar Timing Arrays
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Pulsar timing arrays provide a rare opportunity to probe exotic physics. Potential sources of gravitational waves (GWs) in the nanohertz band include cosmic strings, inflation, and early universe phase transitions. GW observations will also make possible new tests of gravitational theories and provide a means to probe certain dark matter models.
Siemiginowska,AnetaCenter for Astrophysics | Harvard & SmithsonianThe Next Decade of Astroinformatics and Astrostatistics
.pdf
Over the past century, major advances in astronomy and astrophysics have been driven by improvements in instrumentation. With the amassing of high quality data from new telescopes it is becoming clear that research in astrostatistics and astroinformatics will be necessary to develop new methodology needed in astronomy.
Simon,JoshuaCarnegie ObservatoriesTesting the Nature of Dark Matter with Extremely Large Telescopes
.pdf
Extremely large telescopes can critically test the predictions of the LambdaCDM model on small scales via the three-dimensional motions of stars in dwarf galaxies and integral field spectroscopy of gravitationally lensed galaxies and quasars. Such observations will conclusively determine whether dark matter is cold and collisionless.
Simon,RobertUniversitaet zu KoelnThe Cycling of Matter from the Interstellar Medium to Stars and back
.pdf
Many open questions regarding cloud and structure formation, the role of turbulence, and the relative importance of different feedback processes in the interstellar medium can only be addressed with observations of spectrally resolved lines. We here stress the importance of wide field surveys in atomic carbon and mid-J CO lines.
Simon,JoshuaCarnegie ObservatoriesDynamical Masses for a Complete Census of Local Dwarf Galaxies
.pdf
The 2020s are poised to continue the past 15 years of significant advances based on the discovery and follow-up of nearby dwarf galaxies. Maximizing the scientific impact of dwarfs discovered in upcoming imaging surveys will require both major spectroscopic surveys on 6-10m telescopes and multiplexed spectroscopy with even larger apertures.
Slosar,AnzeBroookhaven National LaboratoryDark Energy and Modified Gravity
.pdf
A community umbrella white-paper official endorsed by all main experimental collaborations on the Dark Energy and Modified Gravity research in the coming decade.
Slosar,AnzeBroookhaven National LaboratoryScratches from the Past: Inflationary Archaeology through Features in the Power Spectrum of Primordial Fluctuations
.pdf
This white paper discusses features in the primordial power spectrum of fluctuations as a sensitive probe of inflationary physics.
Smith,J.D.University of ToledoThe Chemical Enrichment History of the Universe
.pdf
We describe the strong role metal abundance plays in galaxy evolution, highlight the need for absolute abundances in modern galaxy formation models, describe current obstacles clouding the cosmic chemical enrichment history, and provide a suite of new and existing methods which can track absolute metal abundance in galaxies across time.
Snios,BradfordCenter for Astrophysics | Harvard & SmithsonianX-rays Studies of the Solar System
.pdf
X-ray observatories advance Solar System studies by probing Sun-object interactions, developing surface composition maps, probing magnetospheric dynamics, and tracking astrochemical reactions. Implementing modern X-ray optics in future instruments will foster a truly transformative era of Solar System science through the study of X-ray emission.
Stanghellini,LetiziaNational Optical Astronomy ObservatoryRadial Metallicity Gradients in Star-Forming Galaxies
.pdf
Radial metallicity gradients of star-forming galaxies have been successfully used to set important constraints on galaxy formation and chemical evolution. This paper focuses on the implications of radial metallicity gradients measured with different probes for a variety of galaxies, and on the foreseen advances in this field in the 2020s.
Stanke,ThomasESOThe warm and dense Galaxy - tracing the formation of dense cloud structures out to the Galactic Center
.pdf
We line out prospects for the coming decade for corresponding molecular and atomic line surveys which are needed to fully understand the formation of the dense structures that give birth to clusters and stars out of the diffuse interstellar medium. This work will require a large Single Dish submm telescope multipixel spectrometer arrays: AtLAST
Stark,ChristopherSpace Telescope Science InstituteOptimal Architectures and Survey Designs for Maximizing the Yields of Direct-Imaging Exoplanet Missions
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Our ability to answer scientific questions about exoplanets hinges on satisfying an age-old astronomical requirement: a sufficient sample size. Thus, the yield of exoplanets is critical to understanding the scientific impact of future missions. We discuss how the yield of directly-imaged exoplanets depends on mission scale and survey design.
Stauffer,JohnCaltech/IPACThe IMF at Very Low Mass Using Near-IR Surveys from Space: The Need for Deep K-band Imaging
.pdf
This white paper describes two observational programs which could be conducted in the next decade which could greatly improve knowledge of the IMF at low masses and advocates a low cost, low risk solution for providing the needed observational capability.
Steiner,James FMITAccretion Physics with Fast X-ray Spectral Timing
.pdf
We demonstrate the enormous progress in our understanding of accretion onto compact objects that can be readily achieved by a next generational large-area X-ray timing instrument.
Stephens,IanCfA/SAOPolarization in Disks
.pdf
This white paper discusses how disk polarization observations can be used to study disk and grain properties during the planet formation process. Such studies require very sensitive and high resolution multi-wavelength observations.
Stinebring,Dan R.Oberlin CollegeTwelve Decades: Probing the Interstellar Medium from kiloparsec to sub-AU scales
.pdf
After a decade of great progress in understanding gas flow into, out of, and through the Milky Way, we are poised to merge observations with simulations to build a comprehensive picture of the multi-scale magnetized interstellar medium. These insights will also be crucial to four bold initiatives in the 2020s: GWs, FRBs, cosmic B-mode, and the EHT.
Su,KateSteward Observatory, University of ArizonaProbing Unseen Planet Populations with Resolved Debris Disk Structures
.pdf
This white paper focuses on resolving debris structures in thermal emission that is applicable to a large unbiased sample. We summarize the properties of the known debris disks and assess the feasibility of resolving them within our current and future infrared and millimeter facilities by adopting uniform criteria.
Su,YuanyuanUniversity of KentuckyA Unification of the Micro and Macro Physics in the Intracluster Medium of Nearby Clusters
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The vast bulk of the hot baryons in the Universe is in the form of the intracluster medium. All major cosmological simulations assume the astrophysical plasma to be inviscid. It is critical to constrain the effective transport coefficient of the intracluster medium to truly understand the baryonic processes in the Universe.
Suntzeff,Nicholas B.Mitchell Institute for Fundamental Physics & Astronomy, Texas A&M UniversityThe Cusp of Discovery in Astronomy
.pdf
In this white paper, I call upon our community to organize our goals behind the theme to discover life elsewhere in the Universe in the next decade.
Tanvir,NialUniversity of LeicesterGRBs as Probes of the Early Universe with TSO
.pdf
Long-GRBs are extremely luminous and trace massive star formation to z>8. Afterglow spectroscopy probes host ISM and IGM on the line of sight, providing abundances, average escape fraction and IGM neutral fraction. The proposed Time-domain Spectroscopic Observatory will provide O/IR imaging and spectroscopy for much larger samples of z>6-12 GRBs.
Taylor,Stuart F.Participation WorldscopeCharacterizing the Distribution of Parameters of Planets Found by Radial Velocity is Essential for Understanding Planet Formation and Evolution
.pdf
mation that can provide essential guidance to understanding the evolution of planetary systems. Structure that depends on the star’s metallicity has been found in the counts of planets by log period. Eccentricity has correlations with planet number, metallicity, aggregate planet count density per log period, stellar multiplicity, and planet mass.
Taylor,StephenCalifornia Institute of TechnologySupermassive Black-hole Demographics &Environments With Pulsar Timing Arrays
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Precision timing of large arrays (>50) of millisecond pulsars will detect the nanohertz gravitational-wave emission from supermassive binary black holes within the next ~3−7 years. We review the scientific opportunities of these detections, the requirements for success, and the synergies with electromagnetic instruments operating in the 2020s.
Taylor,PatrickLunar and Planetary InstitutePlanetary Radar Astronomy with Ground-Based Astrophysical Assets
.pdf
Planetary Radar with Ground-Based Astrophysical Assets
Thilker,DavidJohns Hopkins UniversityThe Nature of Low-Density Star Formation
.pdf
How do stars manage to form within low-density, HI-dominated gas? Here we outline fundamental questions about the nature of star formation at low-density. We describe the wide-field, high-resolution imaging of stars, star clusters, and gas clouds in nearby galaxies needed to provide definitive answers and build a complete theory of star formation.
Timmes,FrankArizona State UniversityCatching Element Formation In The Act ; The Case for a New MeV Gamma-Ray Mission: Radionuclide Astronomy in the 2020s
.pdf
Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. The unique information provided by MeV gamma-ray astronomy to help address frontiers makes now a compelling time for the community to advocate for a new mission to be operational in the 2020s and beyond.
Tinto,MassimoUniversity of California San Diego, Center for Astrophysics and Space SciencesSpace-Based Gravitational Wave Observations in the Mid-Band Frequency Region
.pdf
The opportunity exists to scientifically explore the Gravitation Wave (GW) frequency band that is in between those accessible by LISA and LIGO. This frequency region could be accessible by a low-cost space-based interferometric detector that relies only on laser interferometry technology similar to that flown onboard the GRACE Follow-On mission.
Tkachenko,AndrewInstitute of Astronomy, KU LeuvenGravity-wave asteroseismology of intermediate- and high-mass stars
.pdf
This white paper focuses specifically on the transport of chemical elements and of angular momentum in the stellar structure and evolution models of stars born with convective core, as revealed by their gravity-mode oscillations.
Tobin,JohnNational Radio Astronomy ObservatoryThe Formation and Evolution of Multiple Star Systems
.pdf
Multiple star systems are a frequent outcome of the star formation process and their formation must be studied in the protostellar phase. We review the new directions of research that can be taken in the next decade with current and new facilities, specifically those operating in the millimeter/centimeter radio wavelength range.
Tobin,JohnNational Radio Astronomy ObservatoryMeasuring Protostar Masses: The Key to Protostellar Evolution
.pdf
Our understanding of the early evolution of protostars is limited by our lack mass measurements for the protostellar objects. The masses of protostars can only be directly measured using millimeter interferometry to observe spectral lines from the rotating disks and infalling envelopes, requiring large investments of time and/or facility upgrades.
Toloza,OdetteUniversity of WarwickUnderstanding the evolution of close white dwarf binaries
.pdf
In this white paper we stressed the importance of ultraviolet (high-resolution) and optical (low- and high-) spectroscopy to understand of evolution of close binaries that contain white dwarfs which lead to a variety of outcomes.
Tombesi,FrancescoUniversity of Maryland, College ParkDo Supermassive Black Hole Winds Impact Galaxy Evolution?
.pdf
Powerful winds driven by SMBHs are likely the main mechanism through which SMBHs regulate their own growth and influence the host galaxy evolution. However, their origin and their capability to impact the large-scale environment are still highly debated. Fundamental results will come from high-energy and spatial resolution X-ray observatories.
Tremblay,GrantCenter for Astrophysics | Harvard & SmithsonianGalaxy Winds in the Age of Hyperdimensional Astrophysics
.pdf
Energy feedback has achieved paradigmatic status in the field of galaxy evolution, but many of its key aspects remain unobserved. ALMA and modern IFU spectrographs map galactic winds with unprecedented detail. These observations are equivalent to seeing only sparks in a fire. A next-generation X-ray microcalorimeter is needed to see the flame.
Trilling,DavidNorthern Arizona UniversityOrigins Survey of Primordial Relics: ELTs Reveal Compositional Variation across the Solar System
.pdf
This white paper describes how ELTs (e.g., GMT, TMT) can be used to understand the origins of our Solar System through observations of small bodies (asteroids, comets, etc.).
Tripp,ToddUniversity of Massachusetts - AmherstOn The Unique Value of Spectroscopy in the Deep Ultraviolet for Galaxy Evolution Studies
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We discuss, with real data examples, a largely unexplored discovery space for CGM studies: the diagnostic-rich deep ultraviolet at rest wavelengths < 912 A. The resonance lines of a wide array of ions are in this region, but they can be accessed by studying QSO absorbers with sufficient redshift to bring the lines into the observable UV band.
Tumlinson,JasonSTScI / JHUThe Baryon Cycle, Resolved: A New Discovery Space for UV Spectroscopy
.pdf
Galactic feedback arises from stars, supernovae, black holes, and radiation in a complex interplay that begins at < 100 pc scales. Future advancements in spatially resolved spectroscopy in the UV will provide unprecedented physical resolution in unique and powerful diagnostic features that are not available at other wavelengths.
Turyshev,SlavaJet Propulsion Laboratory, Californa Institute of TechnologyDirect Multi-Pixel Imaging and Spatially-Resolved Spectroscopy of a Potentially Habitable Exoplanet with the Solar Gravitational Lens
.pdf
Direct high-resolution investigations of a potentially habitable exoplanet may result in finding extra-terrestrial life. This can be achieved with a telescope at the focal region of the Solar Gravitational Lens. Resulting facility is the only practical way to achieve a multi-pixel image at a km-scale resolution on the surface of an exoplanet.
Tuttle,SarahUniversity of Washington, SeattleMapping the CGM in Emission
.pdf
Mapping the circumgalactic medium (CGM) in emission is a crucial next step to understand both the baryonic distribution of the universe and the multi-scale multi-phase medium that is a primary mediator of galaxy formation and evolution. Here we discuss the current state of the field and next steps.
Tzeferacos,PetrosUniversity of ChicagoAstrophysical magnetized turbulence and turbulent dynamo in laser-driven plasma experiments
.pdf
This white paper describes recent experimental breakthroughs and research opportunities in laboratory astrophysics on the topics of magnetized turbulence and turbulent dynamo. These fundamental processes are relevant to the evolution and dynamics of the interstellar and intergalactic mediums.
Uzdensky,DmitriUniversity of Colorado BoulderExtreme Plasma Astrophysics
.pdf
This white paper describes the present status and emerging opportunities in Extreme Plasma Astrophysics -- a study of astrophysically-relevant plasma processes taking place under extreme conditions that necessitate taking into account relativistic , radiation, and QED effects.
Valencic,LynneJohns Hopkins UniversityProbing the Structure of Interstellar Dust from Micron to Kpc Scales with X-ray Imaging
.pdf
This White Paper explores the impact that the next generation of X-ray imagers will have on constraining interstellar dust grain models and improving our understanding of the physical processes that dictate how grains evolve over their lifetimes.
van Belle,GerardLowell ObservatoryHigh Angular Resolution Astrophysics: Fundamental Stellar Parameters
.pdf
A discussion of direct determination of fundamental stellar parameters, which has many profound and wide-ranging impacts throughout astrophysics.
van der Marel,NienkeNRC Herzberg Astronomy & Astrophysics programsDust growth and dust trapping in protoplanetary disks with the ngVLA
.pdf
ALMA reveals structures in protoplanetary disks that indicate dust trapping as an important mechanism in the planet formation process, but interpretation is limited due to the optically thick mm emission. The next-generation Very Large Array (ngVLA) will open up the possibilities to study dust growth in disks in optically thin cm wavelengths.
Vandenbroucke,JustinUniversity of WisconsinMulti-messenger and transient astrophysics with very-high-energy gamma rays
.pdf
The discoveries of high-energy astrophysical neutrinos and of gravitational waves, as well as the rise of time-domain astronomy, have revolutionized astrophysics. We describe the prospects for gamma-ray telescopes, particularly in the energy range greater than 20 GeV, for multi-messenger and transient astrophysics in the decade ahead.
Venters,ToniaNASA Goddard Space Flight CenterEnergetic Particles of Cosmic Accelerators I: Galactic Accelerators
.pdf
This white paper is the first of a two-part series highlighting the most well-known high-energy cosmic accelerators and contributions that MeV astronomy will bring to understanding their energetic particle phenomena. The paper discusses galactic cosmic rays, supernova remnants, protostellar jets and superbubbles, and colliding wind binaries.
Venters,ToniaNASA Goddard Space Flight CenterEnergetic Particles of Cosmic Accelerators II: Active Galactic Nuclei and Gamma-ray Bursts
.pdf
This white paper is the first of a two-part series highlighting the most well-known high-energy cosmic accelerators and contributions that MeV gamma-ray astronomy will bring to understanding their energetic particle phenomena. This white paper discusses active galactic nuclei and gamma-ray bursts.
Viana,AionInstituto de Física de São Carlos, Universidade de São Paulo, BrazilSearching for TeV Dark Matter in the Milky Way Galactic Center
.pdf
We present the prospects to detect and identify dark matter particles through the observation of very-high-energy gamma rays coming from the annihilation or decay of these particles in the Galactic halo. Observations with future high-energy observatories would reach unprecedented sensitivity to dark matter particles with masses in the TeV scale.
Vieregg,AbigailUniversity of ChicagoAstrophysics Uniquely Enabled by Observations of High-Energy Cosmic Neutrinos
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This white paper describes the outstanding astrophysics questions that neutrino astronomy can address in the coming decade. Detailed measurements of the diffuse neutrino flux, neutrinos from point sources, and multi-messenger observations with neutrinos will enable the discovery and characterization of the most energetic sources in the Universe.
Vieregg,AbigailUniversity of ChicagoFundamental Physics with High-Energy Cosmic Neutrinos
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This white paper describes the outstanding particle physics questions that high-energy cosmic neutrinos can address in the coming decade. Tests of fundamental physics using high-energy cosmic neutrinos will be enabled by detailed measurements of their energy spectrum, arrival directions, flavor composition, and timing.
Voit,MarkMichigan State UniversityCircumgalactic Gas and the Precipitation Limit
.pdf
Observations increasingly suggest that the ambient CGM pressure cannot exceed the limit at which cold clouds start to condense and fuel feedback that limits further condensation. Such a feedback loop tends to suspend the CGM at the threshold pressure for precipitation. The coming decade will offer many opportunities to test this principle .
Vos,JohannaAmerican Museum of Natural HistoryThe L/T Transition
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The L/T transition is an important evolutionary phase in brown dwarf atmospheres. In the next decade, we will answer three key questions: 1. What is the physical mechanism behind the L/T transition? 2. What is the spatial extent of atmospheric structures at the L/T transition? 3. How do gravity and metallicity affect the L/T transition?
Vulic,NevenNASA Goddard Space Flight CenterTime Domain Studies of Neutron Star and Black Hole Populations: X-ray Identification of Compact Object Types
.pdf
We present requirements for next generation X-ray telescopes that will enable measurements of time domain properties of X-ray binaries to identify black holes and neutron stars.
Wadiasingh,ZorawarNASA Goddard Space Flight CenterMagnetars as Astrophysical Laboratories of Extreme Quantum Electrodynamics: The Case for a Compton Telescope
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Magnetars, the most highly magnetic of the neutron star zoo, will serve as a prime science target for new missions surveying the MeV window. This paper outlines the core questions pertaining to magnetars and quantumelectrodynamic physics that can be addressed by new technologies with spectropolarimetric capability in the 0.1-100 MeV energy range.
Walker,StephenNASA Goddard Space Flight CenterUnveiling the Galaxy Cluster - Cosmic Web Connection with X-ray observations in the Next Decade
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In recent years, the outskirts of galaxy clusters have emerged as one of the new frontiers and unique laboratories for studying the growth of large scale structure in the universe. A next-generation X-ray telescope is required in order to reveal the full story of the growth of galaxy clusters and the cosmic web and their applications for cosmology.
Walter,FabianMPIA/NRAOThe evolution of the cosmic molecular gas density
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This work outlines the importance of cold gas surveys throughout cosmic history, and their prospects to revolutionize studies of galaxy evolution over the coming decade(s).
Wang,JiThe Ohio State UniversityNew Frontiers for Terrestrial-sized to Neptune-sized Exoplanets In the Era of Extremely Large Telescopes
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Detecting and characterizing terrestrial- to Neptune-sized planets (1 < R < 4 REarth) around nearby stars holds the key to understanding the diversity of exoplanets and will ultimately address the ubiquitousness of life in the universe. Here we provide an overview of the challenge and promise of success.
Wang,LifanTexas A&M UniversityJWST: Probing the Epoch of Reionization with a Wide Field Time-Domain Survey
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A public deep and wide science enabling survey will be needed to discover these black holes and supernovae, and to cover the area large enough for cosmic infrared background to be reliably studied. This enabling survey will find a large number of other transients and enable supernova cosmology up to z $sim$ 5.
Wang,Q. DanielUniversity of Massachusetts AmherstThe Panchromatic Circumgalactic Medium
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The circumgalactic medium (CGM) is empirically multi-phased and complex in dynamics. We review progress and open questions specific for the hot component, magnetic fields and cosmic rays, the cool, warm, and dusty components, and conclude with open questions primarily regarding the interplay among different components.
Wang,YunCalifornia Institute of TechnologyIlluminating the dark universe with a very high density galaxy redshift survey over a wide area
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A very high number density galaxy redshift survey over a wide area (HD GRS Wide) spanning the redshift range of 0.5
Weinberger,AlyciaCarnegie DTMA Strategy for Understanding Planet Formation
.pdf
This white paper argues for a pan-chromatic approach to understanding planet formation including observations from X-rays through radio. Planet formation research seeks to address: where planets form in circumstellar disks, how material is transported through the disk and into planets, and how disks evolve in concert with their stars and planets.
Weisz,DanielUniversity of California, BerkeleyNear-Field Cosmology with the Lowest-Mass Galaxies
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We present an overview of near-field cosmology and make recommenations for future progress. The study of nearby low-mass galaxies on a star-by-star basis has implications that extend far beyond the local Universe and include the nature of dark matter, lives and deaths of the first stars, cosmic reionization, and galaxy formation across cosmic time.
Wheeler,J. CraigThe University of Texas at AustinELT Contributions to The First Explosions
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We describe the potential for using Type Ia supernovae, pair instability supernovae, superluminous supernovae, and gamma-ray bursts to probe the first explosions and hence first stars in the Universe with a US-ELT System.
Wheeler,J. CraigThe University of Texas at AustinELT Contributions to Tidal Disruption Events
.pdf
A US-ELT system with its large aperture and sensitive optical and near infrared imager spectrographs will make major contributions to the study of stars ripped apart by supermassive black holes.
White,StephenAir Force Research LaboratoryThe Importance of Synoptic Solar Radio Observations
.pdf
The long history of monitoring the Sun’s radio flux has led to time series of solar activity that reflect the solar cycle and the physical nature of solar radio emission. Here we discuss some of the results of this monitoring and the importance of maintaining this record.
Williams,BrianNASA GSFCFuture X-ray Studies of Supernova Remnants
.pdf
This white paper outlines the progress that can be made from the next generation of X-ray telescopes in the study of the remnants of supernovae, both galactic and extragalactic. We primarily focus on high spectral resolution instruments and the science they will enable.
Williams,DavidUniversity of California Santa CruzProbing Extreme Environments with Very-High-Energy Gamma Rays
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This white paper briefly summarizes what can be learned over the coming decade about extreme astrophysical environments through ground-based gamma-ray observations over the 20 GeV to 300 TeV range.
Williams,BenjaminUniversity of WashingtonFar Reaching Science with Resolved Stellar Populations in the 2020s
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We describe the many fields in astronomy that will benefit from resolved stellar population studies in the 2020s. We focus on the significant progress that we expect from projects currently under construction, and in this context, what will be the most impactful capabilities for which to strive in the longer term.
Windhorst,RogierArizona State UniversityOn the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits
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We discuss if Pop III stars and accretion disks around stellar-mass black holes at z>7 may be directly observable to JWST and the next generation 25-39 meter ground-based telescopes through cluster caustic transits. About 3-30 of the best lensing clusters need to be monitored several times a years for several years to directly detect this.
Wolf,EricUniversity of ColoradoThe Importance of 3D General Circulation Models for Characterizing the Climate and Habitability of Terrestrial Extrasolar Planets.
.pdf
3D GCM modeling is critical for interpreting spectra of exoplanets taken from current and planned instruments. We recommend continued institutional support for 3D GCM modeling teams that focus on planetary and exoplanetary applications.
Wolff,MichaelSpace Science Division, Naval Research LaboratoryThe Physics of Accretion Onto Highly Magnetized Neutron Stars
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Studying physical processes occurring above the magnetic poles of strongly magnetized, accreting neutron stars provides us with a laboratory for studying high temperature plasmas exposed to extreme conditions. This white paper discusses the current theoretical and observational challenges, and the importance of addressing these challenges.
Wolk,ScottSmithsonian Astrophysical ObservatoryX-ray Studies of Exoplanets
.pdf
We discuss contributions to the study of exoplanets and their environs which can be made by X-ray data of increasingly high quality that are achievable in the next 10--15 years.
Wolk,ScottSmithsonian Astrophysical ObservatoryUnderstanding Galactic Star Formation with Next Generation X-ray Spectroscopy and Imaging
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To address problems in the field of star formation adequately, astronomers in the 2030's will require a new X-ray telescope with arc-second imaging and of order 10,000 cm^2 collecting area. This will enable us a community to keep up with the advances which will be enabled by facilities already in development for the 2020s.
Wong,Michael H.UC BerkeleySolar system Deep Time-Surveys of atmospheres, surfaces, and rings
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Imaging and resolved spectroscopy reveal varying environmental conditions in our dynamic solar system. Observatory-level commitments to conduct annual observations of solar system bodies would establish a long-term legacy chronicling the evolution of dynamic planetary atmospheres, surfaces, and rings.
Wood-Vasey,MichaelUniversity of PittsburghType Ia Supernova Cosmology with TSO
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Space-based 1--2.5~m class observatories with imaging and spectroscopic instruments covering $0.3
Wright,JasonPenn State UniversityTechnosignatures in Transit
.pdf
TESS, and similar time-domain photometric projects are well-suited for searches for large artificial structures orbiting other stars in the Galaxy. An effort to identify anomalous transit events in these photometry datasets, and a robust follow-up program to understand them, would enable the first robust upper limits on such megastructures.
Wright,JasonPenn State UniversityTechnosignatures in the Thermal Infrared
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WISE and Gaia ​ provide an opportunity for the first robust upper limits on the energy supplies of extraterrestrial civilizations, both for stars in the Galaxy and for other galaxies. JWST​ will provide the MIR spectroscopy necessary to identify the origin of infrared excesses, advancing both traditional astronomy and searches for technosignatures.
Wright,JasonPenn State UniversitySearches for Technosignatures in Astronomy and Astrophysics
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Recent advances in observation, instrumentation, and our understanding of exoplanets make the search for technosignatures (i.e. SETI) is a compelling scientific theme for the coming decade. This white paper introduces the subject, highlights results from the NASA Technosignatures workshop, and identifies key advances necessary in the next decade.
Wrobel,JoanNational Radio Astronomy ObservatoryIntermediate-Mass Black Holes in Extragalactic Globular Clusters
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Intermediate-mass black holes have masses of ~ 100 to 100,000 Msun. Finding them in globular clusters would validate a formation channel for seed black holes in the early universe and inform event predictions for gravitational wave facilities. Searching many globular clusters is key, and only feasible using a next-generation Very Large Array.
Yan,HuirongDESY & University of PotsdamPrecision measurement of magnetic field from near to far, from fine to large scales in ISM
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Spectropolarimetry from Ground State Alignment (GSA) has been suggested as a direct tracer of magnetic field in interstellar diffuse medium. It provides a unique tool for studies of sub-gauss magnetic fields using polarimetry of UV, optical and radio lines. Both 3D tomography and topology are achievable.
Yee,JenniferCenter for Astrophysics | Harvard & SmithsonianThe Scientific Context of WFIRST, Microlensing in the 2020s
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Rather than providing a broad perspective on the WFIRST microlensing science case, this white paper explores in detail a few specific, well-defined, science questions motivated by recent research that can be answered by the WFIRST microlensing survey.
Yoachim,PeterUniveristy of WashingtonLSST Narrowband Filters
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We discuss the technical considerations of using narrowband filters with the LSST and lay out the scientific impact that would result on the study of AGB stars, emission line nebula (e.g., supernova remnants and planetary nebulae), photometric redshifts of galaxies, and the determination of stellar parameters.
Youngblood,AllisonNASA Goddard Space Flight CenterEUV observations of cool dwarf stars
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The EUV (100-912 Å) probes regions of the stellar atmosphere that are inaccessible from other spectral regions, including cool coronal emission lines that offer the clearest path toward detecting coronal mass ejections on stars other than the Sun. New EUV observations would require a dedicated grazing-incidence observatory.
Youngblood,AllisonNASA Goddard Space Flight CenterEUV influences on exoplanet atmospheric stability and evolution
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EUV photons (100-912 Å) drive atmospheric mass loss, and an accurate accounting of the EUV in a planet's energy budget is essential. Direct EUV observations of exoplanet host stars would require a new, dedicated observatory. Archival observations from EUVE and models are insufficient to accurately characterize EUV spectra of exoplanet host stars.
Yu,NanJet Propulsion LaboratoryExploring Dark Energy and Gravity in Space Laboratories
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Dark energy is one of the greatest mysteries in science today and has the potential for discovery of new physics. Precision space laboratory experiments provide opportunities for direct detection of dark energy as well as help addressing other outstanding science questions in the area of gravity including dark matter and gravitational waves.
Zaritsky,DennisUniversity of ArizonaEmission Line Mapping of the Circumgalactic Medium of Nearby Galaxies
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The circumgalactic medium (CGM) is both the reservoir of gas for subsequent star formation and the depository of chemically processed gas, energy, and angular momentum from feedback. We discuss the opportunity to realize spectral-line images of the CGM in individual nearby galaxies. Such work will happen in the next decade.
Zasowski,GailUniversity of UtahHigh-Dimensional Dust Mapping
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This white paper describes the impact of mapping 3D dust properties in the Milky Way, including extinction curve behavior and dynamics, and the observations needed to achieve these goals.
Zellem,RobertJet Propulsion Laboratory, California Institute of TechnologyEngaging Citizen Scientists to Keep Transit Times Fresh and Ensure the Efficient Use of Transiting Exoplanet Characterization Missions
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This white paper advocates for the creation of a community-wide program to maintain precise mid-transit times of exoplanets that would likely be targeted by future exoplanet characterization platforms. Given the numerous targets that will require careful monitoring, this network will initially be devised as a citizen science project.
Zemcov,MichaelRochester Institute of TechnologyOpportunities for Astrophysical Science from the Inner and Outer Solar System
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Astrophysical measurements away from the 1 AU orbit of Earth can enable several astrophysical science cases that are challenging or impossible to perform from Earthbound platforms. In this White Paper, we describe the science motivations and advocate for flight opportunities to make these science investigations a reality.
Zezas,AndreasCenter for Astrophysics | Harvard & SmithsonianX-ray binaries: laboratories for understanding the evolution of compact objects from their birth to their mergers
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This white paper describes the need for a high collecting area, high resolution X-ray observatory, in order to make the next major advances in our understanding of the formation and evolution of accreting binaries and compact object populations, in synergy with detections of gravitational wave sources and short-gamma ray bursts.
Zingale,MichaelStony Brook UniversityMMA SAG: Thermonuclear Supernovae
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Type Ia supernovae are important as sites of nucleosynthesis and as distance indicators. But remarkably, we still do not have a consensus on the underlying progenitor of these events. Multimessenger observations over the next decade will bring a wealth of new information about SN Ia, allowing us to uncover the origin and mechanism of these events.
Zoghbi,AbderahmenUniversity of MichiganSupermassive Black Hole Spin and Reverberation
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X-ray reverberation mapping has emerged as a powerful probe of microparsec scales aroundAGN, and with high sensitivity detectors, its full potential in echo-mapping the otherwise inaccessible disk-corona at the black hole horizon scale will be revealed.

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