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- TRENDS 202227 Jul, 2022
- Advancing IDEA in Planetary Science 27 Jul, 2022
- The Arecibo Observatory: An Engine for Science and Scientists in Puerto Rico and Beyond27 Jul, 2022
- Cryogenic Frontend work for the 12m telescope entering phase II21 Jul, 2022
- A Parkes “Murriyang” Search for Pulsars and Fast Transients in the Large Magellanic Cloud 11 Jul, 2022
- A Comparison of Multiphase Magnetic Field Tracers in a High Galactic Latitude Region of the Filamentary Interstellar Medium 11 Jul, 2022
- The First Observation of Additional Ionospheric Layers Over Arecibo Using an Incoherent Scatter Radar11 Jul, 2022
- Decoding the star forming properties of gas-rich galaxy pairs11 Jul, 2022
- Crater Ejecta Across Maxwell Montes, Venus, and Possible Effects on Future Rock Type Measurements 11 Jul, 2022
- On Single-pulse Energies of Some Bright Pulsars Observed at 1.7 GHz11 Jul, 2022
- Probing the Local Interstellar Medium with Scintillometry of the Bright Pulsar B1133 + 16 11 Jul, 2022
- Arecibo Celebrates National Engineers Week 06 Apr, 2022
- The Arecibo Observatory at the Upcoming 240th American Astronomical Society Meeting06 Apr, 2022
- The Arecibo Observatory Survey Salvage Committee Report06 Apr, 2022
- Facilities and Operations Update06 Apr, 2022
Byadmin06 December 2019 Astronomy
Image Credit: World Science Festival
Two tests of general relativity were achieved using observations of a binary pulsar from the Arecibo Observatory spanning 2012 - 2018 and archival data recorded between 2005 - 2009 at AO and the Nançay radio telescope, the September publication in Science revealed.
The study’s authors, led by Dr. Desvignes of the Max Planck Institute, used polarization measurements of the pulsar J1906+0746 to show the relativistic spin precession of strongly self-gravitating bodies, likely caused by the misalignment of the pulsar’s spin vector with respect to the binary system’s total angular momentum due to an asymmetric supernova explosion.
“This paper was only made possible thanks to the continuous monitoring with the Arecibo telescope over the last decade,” Dr. Desvignes conveyed. “Arecibo allowed us to probe the pulsar's beam up to the edge where its radio luminosity is so low that any detection would be impossible with other radio telescopes.”
Arecibo allowed us to probe the pulsar's beam up to the edge where its radio luminosity is so low that any detection would be impossible with other radio telescopes. - Dr. Desvignes (Max Planck Institute)
J1906+0746 is a young pulsar with a spin period of ~144 ms that orbits around another neutron star in ~4 hours. When it was discovered in 2004, polarized emission from both magnetic poles were detected. This fortuitous orthogonal alignment of the pulsar to Earth in 2004 was compared with data from 1998 that revealed only one, stronger pulse was detectable in that era, suggesting the effects of relativistic spin precession.
Previous timing analyses of J1906+0746 measured the spin precession rate, the orbital inclination, and the orbital decay of the binary pulsar, which were consistent with predictions from general relativity. The new analysis, which modeled polarization observations (rather than pulsar timing observations) from AO’s Puerto Rico Ultimate Pulsar Processing Instrument (PUPPI) at a frequency of 1.38 GHz, independently confirmed the spin precession rate and determine the inclination without the directional ambiguity of the timing analyses.
The study predicts that Earth-based measurements of the emission from one pole will no longer be detectable between 2028 and 2070, while the opposite pole’s emission will be visible again between 2085 - 2105.
The observed pulse profiles during different epochs were used to construct sky-projected beam maps of radio emission from both magnetic poles and the polarization properties. The maps show that radio emission is not restricted to one side of a magnetic pole and match theoretical predictions of the current density in the polar cap for an orthogonal rotator and the theoretical emission heights from the surface of the pulsar.
These measurements independently determined the portion of the sky illuminated by the pulsar beam (the beaming fraction). The study revealed a large beaming fraction of 0.52 with substantial luminosity variations. Typically, pulsar J1906+0746 is often used to determine the predicted number of Galactic double neutron stars (from which the rate of gravitational wave detections for neutron star mergers in derived); however, the luminosity conal beam used for these predictions is small and more uniform than these observations reveal. The study concludes that the merger rate of double neutron stars cannot be reliably constrained using the simple conal beam model with uniform luminosity as applied for pulsar J1906+0746.
Text provided by Tracy Becker - AO Collaborator/SWRI Postdoctoral Researcher
Keywords:observatory, arecibo, J1906+0746, puppi, Desvignes, relativistic, Nançay, Planck, max, Galactic, Earth