Eleven students from colleges and universities in the mainland and Puerto Rico participated in the NAIC Summer Student Program at the Arecibo Observatory this year. The program also included a local high school science teacher, Jose Gerena, from Luis Munoz Marin public school in Barranquitas. He worked with Jose Alonso on projects in conjunction with the Visitor Center and its teacher training workshops. The students worked on individual research projects in radar and radio astronomy, atmospheric science and computing with their advisors. In addition to a large number of summer student talks by the observatory staff and visiting scientists, the students also had the opportunity to work on several specially designed hands-on observing projects. Mike Nicolls (Cornell University), who was a summer student at the Observatory last year, returned for three weeks to continue research with Sixto Gonzalez and Nestor Aponte. Mike had a very productive and fruitful summer, working on both technical aspects as well as science.

The NSF Research Experience for Undergraduates (REU) program sponsored eight undergraduates and one teacher. The NASA Capability Enhancement program, based at the University of Puerto Rico, sponsored one student, Ingrid Pla Rodriguez, who worked with Sixto Gonzalez and Craig Tepley. In addition, a graduate level student, Samantha Stevenson (Wesleyan University), was supported by funding from the NAIC.

The students had many observing opportunities this summer with the 1000-ft Arecibo telescope. All the students worked on specially designed hands-on observing projects. The topics included pulsar, continuum, spectral-line and radar astronomy, supervised by the observatory staff (Paulo Friere, Ramesh Bhat, Tapasi Ghosh, Chris Salter, Karen O'Neil, Ellen Howell and Mike Nolan). In addition, some students took advantage of the opportunity to work with Yervant Terzian (Cornell University) and Murray Lewis on a radio recombination line (RRL) project. Their observations led to successful detections of several RRLs towards the planetary nebulae and supernova remnants. Along with the students, Lisa Wray, a receiver engineer at the Observatory also took part in the hands-on observing projects. The projects involved planning and performing the observations, reducing and analyzing the data, and giving short presentations on their experience and findings. Three students had their own observing programs as part of their summer projects. The astronomy students will present the results from their summer research at the upcoming AAS meeting in Seattle, Washington (see below for more details).

Rounding out the technical and educational aspect of the summer, the students this year showed an admirable adventurous spirit in exploring life outside the Observatory. Staff-organized trips to local beaches, festivals and attractions only whetted their appetite. They soon took the initiative and guided themselves to almost every corner of the island. They visited the El Yunque rain forest, snorkeled the bioluminescent bay in La Parguera -- a southern beach, visited Luquillo beach on the east side, drove through the famous coffee plantations in the central mountain range, discovered the world-class Ponce Art Museum. Staff member Diego Janches introduced the students to a local diving instructor, and seven out of the eleven students participated in a 20 hour course to obtain their SCUBA diving certification. Not content with covering the island of Puerto Rico, many scouted out neighboring islands including Tortolla, Culebra, Vieques, Mona, St. John and St. Thomas.

Thanks to the administrative staff of the Observatory, the housing situation for this year's students was very convenient and comfortable. All were housed on-site in the Visiting Scientists Quarters. They were provided all the necessities plus some luxuries -- kitchenettes and computers in each housing unit, and satellite TV in some units.

Supported by NSF REU Funds:

Martha Boyer (University of Minnesota) worked on a project that involved studies of pulsar emission regions at multiple frequencies. Her advisor, Yashwant Gupta from National Centre for Radio Astrophysics, India, was on a sabbatical visit at the Arecibo Observatory. The work involved development and extension of the analysis software for a variety of statistical studies of the pulse structure at multiple radio frequencies. The project employed use of some of the high quality single-pulse data taken with the Giant Metre-wave Radio Telescope (GMRT) in India, and also from the Effelsberg 100-m telescope in Germany and the Lovell 76-m telescope in Jodrell Bank, U. K. Martha's work focused on determination of locations of core and conal components of pulsars as a function of the pulse intensity and radio frequency. Their analysis reveal, for most pulsars, the core component arrives earlier in phase for more intense pulses. This shift in phase is seen to be larger for lower frequencies (< 1 GHz), and nearly disappears at high radio frequencies (~5 GHz). These findings are in support of the hypothesis that more intense pulses originate at higher altitudes in the pulsar magnetosphere than less intense pulses. The results will be presented in a poster paper at the winter AAS meeting in Seattle, WA.

Laura Chomiuk (Wesleyan University) studied the connections between SNR G42.8+0.6 and two angularly nearby neutron stars, SGR 1900+14 and PSR J1907+0918. This project employed several radio astronomical disciplines, including pulsar search and polarimetry, HI and OH spectral-line mapping, and full-Stokes continuum mapping. Laura was jointly supervised by Snezana Stanimirovic and Chris Salter, and the project also included Dunc Lorimer (Jodrell Bank), Ramesh Bhat (NAIC) and Dejan Urosevic (Belgrade) as co-investigators. Several interesting results have emerged so far, some being quite puzzling. The L- and S-band continuum maps confirm the SNR to possess a well defined shell showing pronounced edge brightening. The OH 1665/1667-MHz data reveal a small-diameter absorption patch projected against the SNR interior, at a radial velocity of 18 km/s. The line ratios measured for the 4 OH transitions are far from the expected 1:5:9:1 for thermal equilibrium. An HI feature is also evident at 18 km/s, closely mimicking the structure of the SNR. Polarimetry on PSR J1907+0918 yields an RM of 730 rad/m^2. The OH and HI features have a (far) distance estimate of ~11 +/- 3 kpc. This is larger than the estimate of ~5.7 kpc for SGR 1900+14, but not inconsistent with the latest estimate of 7.8 (-1.1, +0.9) kpc for the pulsar. Laura will present her results in the winter AAS meeting in Seattle, WA.

Jose Gerena, a high school science teacher from the Luis Munoz Marin public school in Barranquitas, was the 2002 Teacher-in-Residence at the Angel Ramos Foundation Visitor Center. He worked under the supervision of young Jose Alonso. The teacher takes part in educational research projects, and also contributes to the outreach activities. In his capacity as the resident teacher, Jose was engaged for most of the summer with the organization of the teacher workshop held at the Visitor Center. He designed several experiments for the CBL Laboratory interface that were implemented in the workshop this summer. Jose also prepared the assessment tools for the workshop evaluation.

Andrew Helton (University of Iowa) worked with Slava Slysh from Astro Space Center of the Lebedev Physical Institute, Moscow, Russia, who is on a long sabbatical visit at the Arecibo Observatory. The project involved all-Stokes survey of OH masers of star forming regions, with the specific goal of searching for possible Zeeman pairs. Andrew worked on data taken with the 1000-ft telescope by his advisor prior to his arrival (April 2002) in the summer. The observations were made with the L-wide receiver with the four sub-correlators centered at 1612, 1665, 1667 and 1720 MHz. The observations were aimed at refining the positions and finding potential sources of Zeeman pairs for future VLBI follow up observations. They find eleven possible pairs from the Arecibo data. Additionally, an OH maser was discovered near a known methanol maser 40.2-0.2m, and it was also found to be a source of possible Zeeman pair. As part of this project, Andrew also developed IDL-based routines for the calibration and reduction of all-Stokes data taken with Arecibo. The results will be presented as a poster paper in the 201st AAS meeting in Seattle, WA.

Daniel Kao (Penn State University) worked with Craig Tepley on a project titled "Lidar configuration and observation of Raman scatter from N$_2$ and H$_2$O". The project involved designing and building of a 3-channel lidar receiver for a Nd:YAG transmitter to observe Raman scattering from N$_2$ and H$_2$O. They combined Rayleigh and Raman scatter data from Nitrogen (at 607 nm) to extend the lower range of the atmospheric temperature profile down to 4 km. Observations of water vapor Raman scatter were made at 660 nm, and combined with Nitrogen Raman scatter data to derive the water vapor mixing ratio profile from 2.5 to 11 km. The receiver configuration has been designed such that measurements of Mie scatter will also be possible, and this will facilitate studies of the relative sizes and shapes of aerosols in the atmosphere. Further, when equipped with narrow band-pass filters, observations of both O$_2$ and O$_3$ Raman scattering will be feasible with the same receiver. Daniel presented his work at the Arecibo workshop in the recent CEDAR meeting held in Colorado.

Stephanie Morris (University of Chicago) worked on two different projects. Her main project, under the guidance of Jeff Hagen, involved development of a web-based GUI (Graphical User Interface) for tracking and monitoring the pressure and temperature of the compressors used in the telescope's receiver systems. Hardware to collect these data is currently under construction. The telescope has recently been outfitted with a new wind speed monitor, which logs the wind speed and direction for every second. Stephanie developed a GUI for the display and monitoring of these data. The GUI could be later extended as a web-based tool for the display and monitoring of the compressor parameters. Stephanie also worked on a pulsar astronomy project, under the supervision of Ramesh Bhat, where newly discovered pulsars from the Parkes multibeam survey are used to study the Galaxy's magnetic field structure. She adapted and customized the software to combine pulsar polarization data taken with the WAPP (Wideband Arecibo Pulsar Processor) at different observing days. This will help to improve upon the quality of polarization results, especially for relatively weaker and/or less polarized pulsars. The software will also allow accurate calibration and correction of instrumental polarization, and hence will be an important tool for precision pulsar polarimetry with Arecibo.

Danielle Moser (University of Illinois, Urbana--Champaign) worked with Diego Janches on interplanetary dust studies using the UHF dual-beam radar facility at the Observatory. Data are from observations of micrometeor flux in the upper atmosphere, conducted in January 2002, where three areas of the sky were simultaneously covered, yielding over 20000 events. Danielle's work involved calculation of their line-of-sight velocites, precise in-atmospheric decelerations and determination of the orbits. The analysis reveals that majority of the detected particles have elliptical orbits, suggesting their confinement to the solar system. Danielle studied the orbits of these dust particles, and their distribution with respect to the ecliptic plane, based on a/e (semi-major axis vs eccentricity) diagrams. The diagrams for the north, line and south pointings are very dissimilar, and are suggestive of evolution of dust (the meteorides) along the drag lines. While many particles with a/e combinations along the drag lines are seen farthest (north) from the ecliptic plane, eccentricities approach the parabolic limit of unity for those closest to the ecliptic plane. Such an evolution was predicted by Morfill and Gruen (1979), but was never observed before. This result was presented by Diego in recent ACM conference in Berlin, Germany and its publication is currently under preparation.

Martin Rodgers (Miami University) studied the morphologies of sporadic E layers over Arecibo, using the Arecibo data from years 1995--2000 taken by his advisor, Qihou Zhou and colleagues. Martin developed several IDL-based tools to study the statistical nature of the layers, including layer location, peak electron density, layer thickness and movement of layers. The results were compared for diurnal, seasonal and solar cycle variances, and reveal several interesting trends. The main trend is an inverse relation between the occurrence and intensity of E's to the solar cycle; the number and intensity of layers is lower at solar maximum than those seen at solar minimum. Another intriguing trend is a maximum of occurrences in March and minima in both April and October. Incidentally, by the end the summer, Qihou moved out of the Arecibo Observatory, to take up his new job as a faculty at Miami University. This will give ample opportunity for Martin to continue to work on this project with Qihou. They plan to carry out further detailed research to confirm these trends, and also extend the work through analysis of more data taken over recent years.

Rebecca Wilcox (University of Washington) worked on Arecibo data obtained by her advisor, Karen O'Neil, over recent years, with the main goal of creating a standard galaxies catalog. The work involved reduction and analysis of the data, comparison with the published data in the literature, and detailed examination of different kinds of HI profiles. Rebecca also developed some IDL-based routines to simplify the reduction process, which output a number of parameters including flux and the velocity width. The analysis shows several galaxies where the Arecibo high-resolution HI profiles do not match their previously published descriptions. Specifically, there are profiles that are intermediate between Gaussian (dwarf galaxies) and two-horned (spiral galaxies), where the profiles tend to be "Gaussian-like" but with definite indications of rotation in the form of small horns or flat tops. Additionally, there are several "lopsided Gaussian" profiles for galaxies, where the velocity widths favor two-horned profiles. A plausible interpretation is an imbalance of gas in the galaxy. Further work will involve calculation of distances and HI masses of the galaxies and study of the Tully-Fisher relation. Rebecca will present her results in a poster paper at winter AAS meeting.

Supported by Other Funds:

Julia Deneva (Vassar College) worked with Paulo Freire on developing a method for the determination of the orbital parameters of binary pulsars. The conventional method involved fitting a Keplerian model to a series of period measurements, where the accuracy is limited by the number of measurements and initial guess values. A recent method (Friere et al. 2001) uses the measured pulsar periods and accelerations to determine these parameters, and works even for very sparse data sets. The method is independent of the epochs of individual observations. Julia's work this summer involved its software implementation and testing using simulated data. The new method works well for data sets of 20 or more period-acceleration measurements (elliptical orbits) or just 4-5 period-acceleration measurements (circular case), and yields fitted parameters that are close to those used in the simulation. The uncertainties in the fitted parameters are deduced using Monte Carlo simulation techniques. This method will be particularly useful for weak pulsars where, because of interstellar scintillation, positive detections are often few and far apart in time. It is also the best possible way of obtaining first order estimates of the orbital parameters for use in time/period orbital fitting, even when the sampling is not sparse. This work will be presented in a poster paper at AAS meeting in Seattle.

Ingrid Pla Rodriguez (University of Puerto Rico -- Mayaguez) , an Industrial Engineering major, put her knowledge and skills of optimizing products and quality control in use for the benefit of the Department of Space and Atmospheric Sciences (SAS) at the Observatory. Her project titled "The New and Improved World of SAS" encompassed several smaller projects, most of which were done under the guidance of Sixto Gonzalez. Among her main contributions to the group are creation of a World Days Worksheet to replace the conventional observing log books. Ingrid undertook rather tedious task of converting the information from several log books into these work sheets, and in the process searched for and completed several important information that were lacking in the log books. She also worked on a compilation of all the atmospheric science experiments done with Arecibo since 1994 through June 2002, and also up-dated and extended upon the web-based publication lists of both the SAS group and visiting scientists. Ingrid also took part in some of the Lidar experiments with Craig Tepley, and in Spectral line hands-on observing project with Karen O'Neil.

Samantha Stevenson (Wesleyan University) was jointly supervised by Tapasi Ghosh and Jo Ann Eder. Her research focused on HI evolution studies of infrared (IR) selected active galactic nuclei (AGN) galaxies. HI 21-cm spectra were obtained for four 12 micron selected samples: Seyfert 1, Seyfert 2, starburst and nonactive galaxies. One of the goals was to examine the effects of the infrared selection criterion on the infrared evolution characteristics for the galaxies. A comparison of the HI properties of the nonactive IR-selected galaxies with those for an optically-selected sample of UGC galaxies (Haynes & Roberts 1994) showed no significant difference. Another interesting result is that, while the 12 micron sample shows definite global evolutionary trends, no difference was noted between the evolutions of Seyfert 1, 2, starburst and non-active galaxies. This may indicate that Seyfert 1 and 2 galaxies are not in different evolutionary stages (in a statistical sense), but could be explained through models of the unified scheme for AGN. Future work will involve a more complete collection of infrared data for all galaxies with HI data available, to allow better statistical studies, and also to examine the cross-comparison between different classes of galaxies. Samantha will present her results at the winter AAS meeting in Seattle.

TALKS:

June 7 Introduction to Radio Astronomy for Summer Students

[Lisa Wray, Arecibo Observatory]

June 11 Twinkle, Twinkle Little Pulsar

[Daniel Stinebring, Oberlin College]

June 11 Methanol Masers: Tracers of Star Formation [Jagadheep Pandian, Cornell University]

June 18 The Arecibo Observatory [Daniel Altschuler, Arecibo Observatory]

June 21 Introduction to Radio Pulsars [Paulo Freire, Arecibo Observatory]

June 25 The Ionosphere and Incoherent Scatter Radar [Mike Sulzer, Arecibo Observatory]

June 28 Lidar Studies of the Middle Atmosphere [Jonathan Friedman, Arecibo Observatory]

July 5 Spectral Line Observations of OH/IR Stars [Murray Lewis, Arecibo Observatory]

July 9 Asteroids [Mike Nolan, Arecibo Observatory]

July 10 Geology of Puerto Rico [Ellen Howell, Arecibo Observatory]

July 15 The Planet Earth: A Large Dust Sweeper [Diego Janches, Arecibo Observatory]

July 16 Faint Fuzzy Stuff - What are LSB Galaxies and Why Would Anyone Study Them? [Karen O'Neil, Arecibo Observatory]

July 18 The Square Kilometer Array Radio Telescope [Yervant Terzian, Cornell University]

July 23 Solar System Studies with Radar [Donald Campbell, NAIC/Cornell]

Summer Student Symposia:

July 18 Lidar Configuration and Observations of Raman Scatter from N2 and H2O Daniel Kao

July 23 Hands-on project presentations Summer Students

July 24 Interplanetary Dust Studies Using the UHF Dual Beam radar Danielle Moser

July 29 Mapping Supernova Remnant G42.8+0.6 Laura Chomiuk

July 29 Determination of the orbital parameters of binary pulsars: Elliptical case Julia Deneva

July 31 HI spectral line observations of galaxies Rebecca Wilcox

July 31 HI Evolution Studies of IR-Selected AGN Samantha Stevenson

July 31 Introduction to Sporadic E's and their morphology Martin Rodgers

August 1 Study of the Pulsar Emission Region at Multiple Frequencies Martha Boyer

August 1 The New and Improved World of SAS Ingrid Pla-Rodriguez

August 1 All-Stokes Survey of OH Masers in Star Forming Regions: Search for Possible Zeeman Pairs Andrew Helton

August 7 A Web-based GUI for the Wind Monitor Stephanie Morris