National Radio Astronomy ObservatoryResearch Projects by NRAO Site
National Radio Astronomy Observatory
Earlier in the summer, the Charlottesville students visited Green Bank to
tour the NRAO telescopes located there, to meet members of the Green Bank
staff, and to attend the annual picnic. A highlight of the trip was a tour
of the nearly completed Green Bank Telescope.
One post-season highlight will be the dedication on 25 August of 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 40 ft telescope there is a student telescope, open for any project which students would like to carry out on it (though its instrumentation is limited).
We're very excited about the Atacama Large 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. Students get to see it take shape as the third year of design and development gets underway.
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 produce short reports describing their summer research.
| Date | Person | Item | Location | Time |
| 4 June | open | Students begin arriving | ||
| 16 June | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 22 June | All | NRAO Summer Picnic | ||
| 7 Jul | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 14 Jul | Wootten | From Antenna Temperature to Science | NRAO,Room 317, Stone Hall | 9am |
| 18 Jul | Turner | Interstellar Chemistry | NRAO,Room 317, Stone Hall | 9am |
| 20 Jul | Condon | Radio Sources | NRAO,Room 317, Stone Hall | 9am |
| 21 Jul | Wootten | ALMA | NRAO,Room 317, Stone Hall | 9am |
| 21 Jul | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 21 July | All | Travel to NRAO Summer Picnic | Green Bank | TBD |
| 22 July | McKinnon | Tour of the GBT | Lounge, Green Bank | 10am |
| 22 July | All | NRAO Summer Picnic | Green Bank | Noon |
| 23 July | All | Return from Green Bank | Green Bank | TBA |
| 26 Jul | van den Bout | The Radio Spectrum | NRAO,Room 317, Stone Hall | 9am |
| 27 Jul | Matthews | HI in Nearby Galaxies | NRAO,Room 317, Stone Hall | 9am |
| 1 Aug | Hogg | Radio Stars | NRAO,Room 317, Stone Hall | 9am |
| 2 Aug | Liszt | The Interstellar Medium | NRAO,Room 317, Stone Hall | 9am |
| 3 Aug | Uson | Dark Matter | NRAO,Room 317, Stone Hall | 9am |
| 3 Aug | All | Pizza Lunch with U. Va. | Anna's | 12pm |
| 3 Aug | All | Pizza Extravaganza | Edgemont Road | 4pm |
| 4 Aug | Bradley | Central Development Lab | NRAO,Room 228, CDL, Ivy Road | 9am |
| 4 Aug | Bradley | Central Development Lab Tour | NRAO,Room 228, CDL, Ivy Road | 10am |
| 4 Aug | Bradley | Tour of U. Va. Device Fabrication Facility | U. Virginia, T4 lot, Olsson Hall | 1:30pm |
| 4 Aug | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
| 8 Aug | All | Summer Student Research Symposium | NRAO,Room 317, Stone Hall | 12pm |
| 10 Aug | Hibbard | Weird and Wild Galaxies I Have Known | NRAO,Room 317, Stone Hall | TBD |
| 18 Aug | open | Public Night at McCormick Observatory | at the Observatory | 9pm |
The relationships between SFR determined by optical, radio, and FIR are explored. Using UGC, NVSS, and IRAS catalogs, a SFR at 1.4 GHz was determined for the local universe (within 100 Mpc). This SFR is compared with FIR star formation rates.
21-cm HI data from the Very Large Array (VLA) and optical R- and B- band data from the WIYN telescope are presented for the superthin galaxy UGC711. An HI rotation curve is dervied with two different methods, to determine which is the more accurate in the case of an edge-on galaxy. Beam smearing is taken into account and the mass contribtuion from the stars, gas and halo are determined by deriving equations for each of the components (Vtotal)2=(Vgas)2 +(Vhalo)2, and scaling the mass to light ratio and dark halo parameters for a good fit to the observed rotation curve.
A recent observation indicates that [HCO+]/[HOC+]= 80 pm 26 in the diffuse cloud toward BL Lac. Standard physical models in combination with measured reaction rate coefficients from the UMIST database fail to explain this ratio. The ratio predicts a single formation mechnaism that cannot occur due to the underabundance of the reactants. Other formation mechanisms are ruled out as well, suggesting that a reevaluation of the theory and/or the reaction coefficients is needed, as well as a more accurate measurement of the ratio.
The summer REU program at NRAO/Socorro in 2000 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 2000 REU program at NRAO/Socorro is under the direction of
Chris
Fassnacht ,and
Greg Taylor. Dr Fassnacht is a
Jansky Postdoctoral Researchers
at NRAO/Socorro, and Dr. Taylor is a member of the scientific research staff.
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.
Wednesday - Wednesday Lunch (required)
Thursday - Summer Student Lectures (required -- See lecture schedule below)
Friday - Colloquium (required, when scheduled)
Saturday & Sunday - Tours at the VLA site
cfassnac@nrao.edu
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).
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.
1999 Summer Student Steve Hicks meets Senator Robert Byrd on the occasion of his visit to the Observatory.
1998 Summer and co-op Students and NRAO staff members after a caving trip
(L-R): Frank Ghigo, Jennifer Lockman, Pat Matheny, Ron Maddalena, Nicole
Wiersgalla, and Steve Hicks.
1998 Calendar of Events -- West Virginia
OVLBI and NRAO is to complete the design of our new Peltier controller. This is a 90% hardware and 10% software project, so it would be good to have an EE as opposed to a CE. I think it could be finished in a summer and would help all on the site. There are a few other small things as well, one would be capturing schematics, updating our documentation - pretty boring for most people but a student might be into it.
A project in the cryogenics lab. An automated system for characterizing and logging the cooling capacity of the various refrigerator needs to be designed built and tested. This would be a nice summer long project which could be carried through form design to completion during the summer months. What I have in mind is a test dewar(s) with variable loads on the first and second stages of the refrigerators. A computer controls the energy applied to each load and graphs a load diagram for the particular refrigerator. This project entails thermodynamics, electrical engineering and writing code for the PC.
The project will involve programming in C or C++ for the
Green Bank Interferometer project. It can involve either
1. Developing software for control of two 85-foot telescopes,
in a vxWorks environment. The software would generate commands
for moving the telescope to desired positions, would monitor
the positions and other status information, and would write
the status data in a log file.
or
2. Developing a system for on-line editing and analysis of
data from the Interferometer. Perhaps this will include
an automated way of identifying radio sources that are flaring
or exhibiting unusual behavior, and of identifying hardware
problems.
Two REU students conducted research at the NRAO Tucson site in Arizona during the summer of 1999. The program in Tucson is under the direction of Jeff Mangum. 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.
In addition to the general activities carried out at the KPNO/NOAO offices, the NRAO and KPNO/NOAO REU students participated in two group activities organized by the NRAO staff. The first was a night at the 12 Meter Telescope, where the REU students spent a day at the 12 Meter Telescope. Following a tour of the telescope and lab facilities, where the students were introduced to the instrumentation used in millimeter wavelength astronomy, the students were given the opportunity to participate in some actual millimeter wave astronomical observations. With this experience the students got an introduction to the observing techniques used in millimeter wavelength astronomy.
The second general activity was a lecture series on millimeter wavelength astronomy given by members of the NRAO scientific staff. Three lectures were given. Jeff Mangum gave a presentation on millimeter wavelength research into the properties of objects in the Solar System and molecular clouds. Darrel Emerson gave a lecture on millimeter wavelength observing techniques. Finally, to complete the survey of millimeter astronomy, Simon Radford gave a lecture on extragalactic astronomy at millimeter wavelengths.
The following are detailed reports describing the work done by each REU student at NRAO Tucson.
My project was a study of star formation and molecular clouds using data from the Five College Radio Astronomy Observatory's CO Outer Galaxy Survey (Heyer et al. 1998, ApJ Suppl,115,241) and the IRAS point source catalog. The CO survey contains more than 2 million spectra and is the most detailed millimeter spectral line map ever made. It covers approximately 300 square degrees of sky in the outer Perseus arm of the Galaxy.
The beginning of the project consisted of a general overview of the properties of molecular clouds in the outer Galaxy, including analysis of their masses, volume densities, sizes, dynamics, and temperatures. As a familiarity with these characteristics was developed, the project shifted into an examination of star formation within the clouds of the survey.
Using the IRAS point source catalog, I created images of the clouds and embedded stars using IDL. After thorough analysis of the IRAS sources' spectra, two samples of clouds were compiled: one of clouds with embedded stars and the other of clouds without embedded stars. Many comparisons between these two samples were made to bring out any characteristics that are indicative of star formation. Specifically, I found a relationship between the samples that suggests that most of the integrated mass of clouds with embedded stars is in a much higher mass range than that of the clouds without embedded stars. Additionally, comparing the column densities of the two samples revealed signs that clouds with embedded stars are more compact than those clouds without stars. These results affirm that molecular clouds that are more massive and compact are likely to have greater star formation efficiencies.
Historically, the inversion transition of ammonia (NH3) has been used as the primary temperature indicator in dense molecular clouds. However, the physical approximation typically used for this method assumes that only three energy levels are populated. This model breaks down when the temperature becomes high enough, about 50K. Recent investigations designed to determine the temperatures of the cores of molecular clouds have found that many of them to be at about 70-150K. As these temperatures are beyond the range of accuracy of the NH3 inversion transition method, these numbers have significant inaccuracies. We propose a different temperature probe which retains its accuracy at higher temperatures than the probes previously used. This probe uses the rotational transitions of methyl cyanide (CH3CN), a symmetric rotor. Using measurements of the J=6-5, 8-7, and 12-11 rotational transitions of CH3CN obtained with the IRAM 30m Telescope, we have derived the kinetic temperature within a sample of molecular cloud cores. The analysis of these data used two separate analysis methods; a statistical equilibrium technique which compared the intensities of the different K-transitions within a given J-ladder, and a rotational temperature diagram analysis. The results of this analysis has yielded good temperature and column density figures for some 24 molecular cloud cores within our galaxy. The results of this work will be presented at the AAS meeting in Atlanta, Georga in January 2000.