National Radio Astronomy ObservatoryResearch Projects by NRAO Site
National Radio Astronomy Observatory
Many of the students in the NRAO-Green Bank program will visit Charlottesville for a tour of the Central Development Laboratory , and of the University of Virginia's facility for the fabrication of the Semiconductor-Insulator-Semiconductor detectors used in millimeter wave receivers, the Semiconductor Device Laboratory.
The students will enjoy an informal get-together with astronomers from the University of Virginia at lunch, and from NRAO in the evening, followed by a visit with graduate students from the University's Astronomy Department.
Later in the summer, the Charlottesville students will visit Green Bank to use the NRAO telescopes located there, to meet members of the Green Bank staff, and to attend the annual picnic.
The students will give a series of 15 minute talks on their projects during a lunch symposium in Charlottesville before they begin leaving for the summer. They will produce short reports describing their summer research.
One highlight will be the placing of the surface onto the Green Bank telescope ( GBT ), the world's largest steerable telescope. It is an offset parabaloid, 110m across the longest axis, incorporating 16 million lbs of steel in the moving structure. The surface is now nearly complete on the ground, where it must be assembled first with supports. During June, the supports will be removed and the surface allowed to sag so that measurements may be made which will assure accurate mounting on the support structure. Then it will be disassembled in sections and moved by crane to the final position on the support structure. This will be particularly interesting. Although we have the largest crane in the US on site, standing some 400 feet high and delivered in five dozen tractor trailers, it cannot reach the whole surface of the telescope. The plan is for the central section to be moved first, after which an auxiliary crane will be erected in the central hole. Distant sections will then be snatched up by the central crane, and handed off in midair to the larger crane, which will hoist them to the surface. This will occur in July through the early fall, and we will go to Green Bank for observations, so should be able to watch the process.
During the course of the summer, the students will conduct a short observing project in Green Bank on the 43m telescope, and tour the Green Bank Telescope, in the final phase of construction this summer. The 40 ft telescope there is a student telescope, open for any project which studets would like to carry out on it (though its instrumentation is limited). If there is interest, we may carry out, probably remotely, a project on the VLA or 12m telescope in Tucson.
We're very excited about the Millimeter Array, which was selected as the top priority for a new astronomical instrument in the 90s back at the beginning of the decade by the Astronomy Survey Committee. It is in the President's budget request this year.
| Date | Person | Item | Location | Time |
| 6 Jun | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 9 Jun | Wootten | Orientation | Rm 317 ER | 0900 |
| 20 Jun | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 23 Jun | Wootten | Orientation | Rm 317 ER | 0900 |
| 23 Jun | Uson | Abell 2029: The Biggest Trash Heap in the Universe | Rm 317 ER | 0900 |
| 25 Jun | Wells | The GBT: The Ultimate Radiotelescope | Rm 317, | 9am |
| 27 Jun | Condon | Radio Sources | Rm 317, | 9am |
| 2 Jul | Kaplan | Pulsars | Rm 317, | 9am |
| 7 Jul | Wootten | Dense Clouds; Interstellar and Cometary | Rm 317, | 9am |
| 8 Jul | Bradley | Central Development Lab Introduction | Rm 228 Ivy Road | 9am |
| 8 Jul | Bradley | Tour of Central Development Lab | Rm 228 Ivy Road | 10 am |
| 8 Jul | Bradley | Tour of UVa EE Applied Electrophysics Laboratory | U. Va. | 1:30 pm - 3:30 pm |
| 8 Jul | Wootten | BBQ in the Wootten's backyard, | 1714 Solomon Rd. Ch'ville 971-6518 | 6pm - 8 pm |
| 9 Jul | Bridle | Jets, Radio Galaxies and Quasars | Rm 317, | 9am |
| 11 Jul | Simon | Extrasolar Planets and New Instruments for Their Detection | Rm 317, | 9am |
| 11 Jul | Hollywood | `Contact' opens nationally | theatres | various |
| 14 Jul | Wiseman | Young Stars | Rm 317, | 9am |
| 15 Jul | Uson | Radio Interferometry | Rm 317, | 9am |
| 16 Jul | Zensus | The VLBA: Imaging Active Galactic Nuclei | Rm 317, | 9am |
| 18 Jul | Turner | Interstellar Molecules and Their Chemistry | Rm 317, | 9am |
| 18 Jul | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 21 Jul | Garwood | AIPS++ | Rm 317, | 9am |
| 23 Jul | Kellerman | Accidental Radio Astronomy | Rm 317, | 9am |
| 24 Jul | Schulman | Life in the Universe I | Rm 317, | 9am |
| 25 Jul | Schulman | Life in the Universe II | Rm 317, | 9am |
| 25 Jul | Kaplan | Travel to Green Bank for Observatory picnic, tours, etc. | CV students overnight Green Bank | |
| 26 Jul | GB Picnic | CV students overnight Green Bank, | ||
| 27 Jul | Kaplan | Return from Green Bank after lunch. | ||
| 28 Jul | Brown | Galaxies at High Redshift | Rm 317, | 9am |
| 30 Jul | open | |||
| 1 Aug | Cotton | Radio Luminosity Functions of Galaxies | Rm 317, | 9am |
| 1 Aug | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 5 Aug | Students | REU research presentations | Rm 317, | high noon |
The project is to refine the determination of the local radio luminosity functions of active galactic nuclei (AGN) and normal galaxies based on flux density measurments from the NVSS 20 cm survey. This survey detects roughly half the nearby galaxies. Previous work has used approximately 4000 UGC galaxies with accurate position and using IRAS 60 micron flux densities to distinguish AGN from normal galaxies. One activity of the student would be to invesitgate individual objects of uncertain classification. Another is to help prepare the results for publication.
The main project which I am working on now is the NRAO VLA Sky Survey (NVSS). This is the largest radio survey ever made, and it will yield almost 2 X 10^6 sources by the time the data reduction is finished sometime this summer. The NVSS is sensitive enough to detect radio emission from most nearby (D < 100 Mpc) galaxies, a mixture of "normal" galaxies, starburst galaxies, and galaxies containing massive black holes. The radio positions are sufficiently accurate for cross-identifications with sources found in other wavebands (e.g., far-infrared sources detected by the IRAS satellite or X-ray sources found in the ROSAT survey). In fact, the superior NVSS positions often allow the far-infrared or X-ray sources to be optically identified with faint galaxies and quasars for the first time. You could work on a project of your choice using the NVSS and other data to study starburst galaxies, X-ray galaxies, etc.' Mr. Kaplan's email address is kaplan@spacenet.tn.cornell.edu
The summer student will work with me on a search for high-velocity neutral hydrogen using Very Large Array observations of the spiral galaxy NGC 1300. The student will calibrate and reduce the VLA observations using AIPS techniques that have been recently developed. The Groningen Image Processing System (GIPSY) will be used to model NGC 1300 for the purpose of identifying high-velocity neutral hydrogen. The observations will be compared with optical images that I have already obtained and reduced. The star-formation rate in the galaxy will be estimated from IRAS obserations available via the Internet, and from VLA radio continuum data.
The student will have a choice of projects, both of which should lead to publications. In one, we will investigate how to employ observations of the submillimeter spectrum of formaldehyde to constrain conditions in regions of massive star formation. Observations from the CSO are already in hand; a preliminary report was delivered at the Toronto AAS meeting. Alternately, the student will help in the reduction and interpretation of observations of molecular emission from Comets Hyakutake and Hale-Bopp. Mangum and I hope to obtain an image of Hale-Bopp in various lines of formaldehyde and methanol to augment data already in hand. This data should reveal the temperature structure of a cometary coma for the first time.
The summer REU program at NRAO/Socorro in 1997 consists of 4 main categories
of activity:
1 - student research projects, in collaboration with an
NRAO advisor
2 - lectures to the students by NRAO staff members
3 - a joint student project, involving observations with the
Very Large Array (VLA)
4 - guided tours of the VLA, given by the students on weekends
The 1997 REU program at NRAO/Socorro is under the direction of
Min Yun , assisted by
Jim Herrnstein and
Tim Bastian. Drs. Yun and Herrnstein are
Jansky Postdoctoral Researchers
at NRAO/Socorro, and Dr. Bastian is a member of the scientific research staff.
Student Research Projects
Each of the REU students will work with one or more advisors on one or more
projects throughout the summer. This is the main focus of the program, and
the majority of the students' time will be spent on these research endeavors.
These projects involved observing, data reduction and analysis, equipment
development, and theoretical studies. At the end of the program, each student
gave a lunch talk explaining the main project(s) he or she worked on during
the summer. The possibility exists for the students to present their original
research at scientific meetings deemed appropriate by their advisor(s).
Following is a detailed list of the specific projects carried out by the
NRAO/Socorro REU students:
The project is to determine the proper motions of a group of about 20 pulsars using VLA data . The observations that exist now are three epochs ; fall 1992, early 1994 and mid 1995 - all A array data. The VLA was used in a gating mode to observe the pulsars using the Princeton timing machine. One IF is gated and the other is not; the latter is used to observe calibrators and background sources . The psr positions are observed with higher signal to noise in the first IF; the postion reference is set by the second IF. The purpose of the project is to reduce the data and determine the psr positions after correcting for a number of effects . RThe collaborators are Goss, Thorsett ( Princeton ) and Fruchter ( Space Telescope ).
Together with Rene Vermeulen (NFRA) I've been investigating the low frequency structure of 3C84 = NGC 1275 using the VLBA (Taylor \& Vermeulen 1996, ApJL 457, L69). This famous radio source is relatively nearby at z=0.0172 and thus makes an excellent "laboratory" for studying the physics of AGN and their environment. This source consists of a jet expanding subluminally to the south out to a total length of 0.1" (24 pc) at 20cm, and a free-free absorbed counterjet seen so far only at shorter wavelengths a few parsecs north of the core (Vermeulen et al 1994, ApJL 430, L41; Walker et al 1994; ApJL 430, L45). We have carried out VLBA observations at 20, 50 and 90 cm (project BV14) of 3C84 in order to study the overall extent of the radio source and its spectrum. A particularly interesting possibility is that the northern jet may become detectable at low frequencies once it has emerged from behind the nuclear disk. A summer student working on this project would learn about the physics of AGN and the reduction of VLB data, including high dynamic range imaging.
We have imaged several Seyfert galaxies with the VLBA, and recently had proposal BU008 approved for four more objects, which would be observed on February 5. The observations of each galaxy would be made at several different frequencies: 18 cm, 6 cm, and either 3.6 or 2 cm. Most would be phase-referencing observations, but one galaxy, Mrk 348, is definitely strong enough so that phase referencing will not be required. We would basically ask a summer student to learn how to reduce VLBA data and to process a single galaxy, probably Mrk 348 because it will be the strongest source. The results would be continuum images and measurements of the spectrum of the source components. Ultimately, when we have all 8 galaxies processed, we hope to make some preliminary estimate of whether there are differences in the VLBI structures of Seyfert 1 and Seyfert 2 galaxies; potentially, the student might also work on this aspect of the project. It is hoped that there will be compact components near the core of at least some of the four galaxies we observe in February, so that a second epoch might be proposed later to check for motions.
By summer 1997 nearly two years of VLBA phase-referencing test data taken to examine the phase stability at the various antennas will be available (~20 experiments). Analysis of this data involves the characterization of the antenna phase stability as a function of weather, season, time-of-day and target-calibrator separation. Other factors such as calibrator structure and ionospheric effects could also be explored if time allows. The results of this analysis would be of immediate interest to the VLBI/VLBA community, and would certainly be published.
Ms. Bryant will study of the relative elemental enrichment of HII regions in NGC 1232. This summer student project is part of a larger project to understand the production/retention of nitrogen and oxygen in spiral galaxies. By looking at one galaxy in detail, we will attempt to constrain the effects of delayed delivery of nitrogen and local mixing. The project will include some data reduction of optical spectra obtained with the Palomar 5m, analysis of emission line strengths to determine abundances, and the creation of code to model nitrogen and oxygen enrichment and mixing processes in a differentially rotating system.
Mr. Reddy will perform a large statistical study of radio properties of a FIR selected complete sample of galaxies taken from the new 1.2 Jy catalog compiled by M. Strauss. The main part of the project is to cross-correlate the new Strauss catalog with the FIRST and NVSS database and obtain the radio and FIR data on a well defined complete sample of galaxies. The radio-FIR correlation and redshift dependent properties will be analyzed from the new database. There are other published studies of radio-FIR relation, but none with this large sample and well defined selection critiria. The results should be publishable and should be presented by the student in a scientific meeting afterwards.
Lectures, etc...
Several lectures about radio astronomy and interferometry will be presented,
allowing the students to obtain a good understanding of the technique. Talks
were also given on general topics in astronomy, presented by members of the
scientific staff. The astronomy talks were designed to give the students an
understanding of what sort of research goes on at NRAO, and in radio astronomy
in general. The detailed list of lectures and events for the summer is in the
following table.
1997 Calendar of Events -- New Mexico
Joint Student Research Project
Students conducting their research at the NRAO Green Bank Site in West Virginia included the students in the list below, along with others. The program at Green Bank is under the direction of Dr. Ron Maddalena.
1997 Calendar of Events -- West Virginia
Phase 1: Develop a UNIX shell level interface to the GBT monitor and control interfaces. This would involve the development of seven small C++ programs (see manual page GBT(1) attached) based on code already written for the Spectral Processor (sps, abort, and spe; see Spectral Processor documentation), but generalized to handle all GBT interfaces. These programs will provide access to all parts of the system, just as the current console or Glish interfaces.
Phase 2: Define a Tcl/Tk interface on top of the seven programs described in Phase 1.
Observations of helium radio recombination lines have been observed with the 140 Foot telescope in a sample of HII regions in the Galaxy. The goal is to produce accurate 4He/H abundances. The project would require the student to help in the observations (if time is allocated), the data reduction and analysis.
The 140-foot telescope at the National Radio Astronomy Observatory in Green Bank, West Virginia is being used to map the 21-cm (1420.40580 MHz) spectral line emission of neutral hydrogen (HI) in the region 65° New data was taken this July. Data reduction algorithms were designed and improved.
Students conducting their research at the NRAO Tucson Site in Arizona included Matt Pickard and Ryan Roth. The program in Tucson is under the direction of Jeff Hagen. As the NRAO offices are across the street from KPNO/NOAO offices, the REU group shares in the activities of the NOAO REU program there.
Images of the CS and H2CO emission toward the Serpens star formation region have been made using the On-The-Fly (OTF) observing technique at the 12m telescope. The project will involve analysis of these data to (1) derive the spatial correspondence between the CS and H2CO emission; (2) measure the spatial density and kinetic temperature in the cores which compose the region; (3) study the kinematic structure of each core to investigate the presence of infall, outflow, or rotation; (4) develop a model of the evolution of the high-density cores within the region. The projects will require that the student become versed in the use of AIPS and an LVG radiative transfer model.