Previous NRAO Summer Student Research Project Summaries
For descriptions of the individual summer programs,
including itineries, pictures, lectures, and joint student projects,
see the previous
Program Reports.
Select a date range, student program, and site below:
Crystal Anderson, of New Mexico Institue of Mining and Techology,
worked with Debra Shepherd on
Multiwavelength detailed study of two young massive stars
Crystal Anderson continued to work on a project with Debra Shepherd and Peter Hofner, which emphasized two different detailed studies of high mass star forming regions: IRAS 20126+4104 and IRAS 18566+0408. I20126 was observed with the Chandra X-Ray Observatory while I18566 was observed with CARMA. The main goals of this work are to study possible accretion disks and outflows associated with the massive young stellar objects. Both projects are part of Crystal's PhD thesis.
The IRAS 20126+4104 region is a prime candidate for accretion and outflows/jets. Previous VLA observations indicate that it is a binary system with an ionized jet (I20S) south of the main, early B protostar (I20126). The Chandra X-ray observations of the cluster were studied for possible X-ray emission from accretion disks, magnetic reconnection events between the disk and young stellar object, and/or colliding binary winds. The surrounding cluster contributed 150 X-ray sources which were individually analyzed for pre-main sequence emission characteristics. Strong X-ray emission was detected from I20S, an ionized jet located 0.8 arcsec south of the early B young stellar object, but not from its more massive cluster member, I20126. However, X-ray and radio emission were found in shock boundaries created within the I20126 jet.
Previous millimeter and VLA observations of IRAS 18566+0408 indicate that the region harbors a massive protostar surrounded by a neutral torus or flattened, rotating core and an ionized jet perpendicular to the torus. Our high resolution CARMA observation of IRAS 18566+0408 in the molecular tracers CH3CN and 13CS were designed to study the distribution and kinematics of the dense gas surrounding the central protostar. We have reduced the data and have detected CH3CN and 13CS and will continue to work on further imaging and analysis of this region.
Benjamin Breslauer, of Oberlin College,
worked with Dale Frail on
Astronomy in the Time Domain
The radio sky is not static and unchanging, but rather there exists a rich variety of objects that vary on a range of timescales. Many possible objects may be responsible for these variations, including, but not limited to, brown dwarfs, old neutron stars, and high redshift galaxies. This summer, we looked into a number of these objects. We searched for radio emission from all known AM CVn stars, and analyzed data from a new type of radio supernova search, finding a number of possible optically-obscured SNe. In addition, we took nightly observations of the many sky positions with the VLA in order to look for radio transients that exist on day-long timescales. We reduced the data in near-real-time in order to make follow-up observations with telescopes in other areas of the EM spectrum, including Palomar and SWIFT.
Stephanie Capen, of Eastern Nazarene College,
worked with Lorant Sjouwerman & Mark Claussen on
Infrared colors of evolved stars as a tracer of maser emission
Stephanie's REU project investigated a universal translation between
the near- and mid-infrared color schemes used in the different space
missions (IRAS, MSX, Spitzer). The project included the retrieval of
the data from the individual web servers, development of computer
programs to match data from the different missions to single sources,
and predict the detection of SiO masers from the colors of the
different space missions. She was able to find two MSX color-color
diagrams (A-D vs. A-E & A-E vs. C-E) that clearly translated the IRAS
two-color diagram regions (as done by van der Veen and Habing 1988)
into a similar sequence of distinguishable MSX color-color
regions. She also looked at a list of 86 GHz SiO maser detections and
statistically predicted the probability of finding SiO maser emission
from the MSX colors she had selected for her figures. In first
instance the scheme is being applied and working for evolved stars
with circumstellar envelopes, after which it can be tuned to include,
e.g., OH and H2O masers, proto-planetary nebulae, planetary nebulae,
or even high-z starburst galaxies.
Jessica Coakley, of Bridgewater College,
worked with Jeff Mangum on
The Star Formation Environment of Sharpless 106
Sharpless 106 (S106) is a bipolar HII region in the Cygnus X molecular cloud complex. It has been studied at radio, infrared, and optical wavelengths, but some aspects of the region still remain a mystery. The purpose of my project was to (1) Create a kinetic temperature map of the NH3 from the (1,1) and (2,2) line data; (2) develop a model for S106 to explain the dynamics of the region, including the IRS sources, the dense gas structure, S106IR, S106FIR, the bipolar outflows, and the temperature; (3) determine an evolutionary scenario for S106 based on the existing knowledge of the region.
The central exciting star of S106 is S106IR/IRS4, which is buried in the dense molecular cloud core from which it recently formed. S106IR has created bipolar outflows bifurcated by a dark lane in the optical and infrared. The dark lane has been explained as a disk (Sibille et al. 1975), torus (Little et al. 1995), ring (Luoshin et al. 1990), or a clumpy molecular cloud (Barsony 1989). A clumpy molecular cloud seems most likely since this is a young stellar object in the stages before disk formation. The outflows have created an ionization front bounded by several IRS sources that were identified by Gehrz et al. in 1981. These IRS sources include S106FIR/IRS3, a possible Class 0 protostar, or more likely just a heated clump that may eventually form a protostar. A C-shock is created in front of the ionization front, which heats up the surrounding molecular cloud, giving it a temperature of between 25 and 40 K with even warmer clumps. The distance to the region is highly uncertain because it is in a tangent arm of our galaxy. Most authors adopt a distance of 600 pc from Staude et al. in 1982, however Schneider et al suggested a distance of 1.7 kpc in 2007 to identify S106 with the Cygnus X region, which seems likely. S106 is probably representative of a system in which a late Class 0 or early Class I protostar is forming in a large, extended molecular cloud, which explains the dynamics of the region.
Claudia Cyganowski, of University of Wisconsin-Madison,
worked with Crystal Brogan on
Probing the Nature of Extended Green Objects: A New Sample of Massive Protostellar Candidates
This project explores the nature of a new sample of massive protostellar candidates identified on the basis of extended 4.5 micron emission in the Spitzer GLIMPSE survey of the Galactic plane. These sources, referred to as "EGOs" (Extended Green Objects) are thought to harbor massive protostars in early stages of evolution, that have been missed by earlier surveys like IRAS. The extended 4.5 micron emission is thought to trace shocked gas in massive protostellar outflows; the goal of my project was to test this hypothesis via EVLA surveys for 6.7 GHz and 44 GHz methanol masers towards a sample of ~ 30 EGOs. The detection rate for 6.7 GHz methanol masers--found only in massive star forming regions-- towards EGOs is at least 64%, significantly higher than the detection rate in previous IRAS and water-maser selected surveys. The subsample of EGOs with 6.7 GHz detections was searched for 44 GHz Class I methanol masers, which are indicative of molecular outflows: the detection rate was 89%. These results indicate that extended 4.5 micron emission is identifying a population of very young
massive protostellar objects, with active outflows, most likely
powered by ongoing accretion. The next stage of this project is to
reduce recently-acquired high resolution mm observations of a
subsample of 4 EGOs to identify and characterize the driving
protostars and study the outflow chemistry.
Frederick Davies, of New Mexico Tech,
worked with Craig Walker and Joan Wrobel on
Relative Motions of two Massive Galaxies in the Virgo Cluster
We used existing VLBA phase reference data at 43 GHz to look for changes in the relative positions the cores of M87 and M84. M87 is
the dominant galaxy of the Virgo Cluster and M84 is one of the most
massive cluster members. The object of our project is to obtain a
time sequence of relative position measurements with accuracy
significantly under 100 microarcseconds using existing data from 2001,
2004 and from an M87 movie project made during 2007 and early 2008. A
measurement of, or upper limit for, a linear motion would constrain the relative motion of the two galaxies and has the possibility to provide the first transverse motion measurement of a galaxy in the heart of the Virgo Cluster. The dense data from the recent movie project will also be used to constrain any changes of the position of the brightest feature. If that feature is actually a feature of the jet that is offset from the black hole, it could potentially wander around depending on jet strength or other factors.
For the summer project, the student reduced the phase referencing
data from many of the recent data sets. In the process, the student did the basic calibration and imaging for many of the data sets and repeated that calibration for all data sets involved in the proper motion project to insure that consistent methods were used. During the reduction, the student determined improved atmospheric calibration using multi-band delay measurements of many calibrators, where available, or phase rate measurements on M87 and two other calibrators. An attempt was also made to improve the calibration for the earlier data since any rate measurement depends very strongly on the 2001 data. As a byproduct of the imaging effort, a light curve and images were produced that will be used to constrain the location of the source of a TeV flare that occurred during the early 2008 observations.
Kiruthika Devaraj, of Georgia Institute of Technology,
worked with Brigette Hesman & Bryan Butler on
Radio Observations and Radiative Transfer Modeling of Planetary Atmospheres
There is significant uncertainty in the structure of the deep atmosphere of Uranus. Uranus has just passed its equinox in 2007 and this is a crucial time for re-investigation of previous data and comparison against recent observations to look for changes, with season, in the deep atmosphere. Radio observations are well suited to sensing the middle to lower troposphere and are used to determine the temperature and chemical structure of Uranus.
This project would involve data reduction of current and previous VLA observations of Uranus. In addition, radiative transfer models of Uranus’ atmosphere will also be updated in order to improve temperature and abundance determinations from VLA observations. Modifications to the model could also be used to investigate emission from the atmosphere of Venus.
This project is best suited to a graduate student interested in planetary research at radio wavelengths.
Three main topics were completed during Ms. Devaraj's project: i) the brightness temperature model for Uranus was updated to work in the microwave region; ii) VLA Uranus data from 2006 and 2007 were reduced; and iii) Venus data from 1996 and 1997 were reduced. Specifically the following in each topic was covered:
i) K. Devaraj has worked extensively on updating the absorption due to the microwave absorbers NH3, H2S, H2O, PH3, and CO for the Uranus model. In addition, the latest saturation vapor pressure curves and deep atmosphere abundances have been updated for these species. While working on these topics it was determined that cloud opacity was an important component missing from the model and this module is now almost complete. Therefore, the update to the Uranus model has been extensive which will allow more accurate temperature and abundance retrievals to be performed from VLA observations.
ii) Three data sets were reduced during K. Devaraj's summer project. A C-band observation from May 2006, and two K-band observations from fall 2007. These observations show Uranus with two bright poles; an unexpected feature since its north pole has been in darkness for nearly 40 years. The data reductions resulted in maps which will then be used along with the updated model to determine tropospheric temperatures of the warm polar regions.
iii) Three data sets were reduced during K. Devaraj's summer project; Venus X-Band data taken in April, 1996 and U-Band and K-Band data taken in December, 1997. The small tilt of Venus (2.6 degrees) results in both poles almost always visible to the sun, and therefore both hemispheres are expected to be at the same temperature. The U and K band maps show that the southern hemisphere is clearly brighter than the northern hemisphere. We are still trying to understand the reason behind this difference in brightness temperature in the two hemispheres.
Robert Edmonds, of The University of New Mexico,
worked with Jeff Wagg & Chris Carilli on
An EVLA study of H2O megamasers in submm galaxies
Traditional methods of measuring redshifts for submm galaxies requires large amounts of telescope time in order to 1) localize the correct optical/infrared counterpart with VLA interferometry at 1.4 GHz, and then 2) measure a redshift through deep spectroscopy with 10-m class optical telescopes. There are many uncertainties in this process, and the success rate for bright submm galaxies is ~40%. Alternative methods, such as broadband searches for CO line emission, may be more effective and cheaper with the current generation of mm-to-cm wavelength facilities. This proposed study explores a new technique involving searches for low frequency water megamaser line emission in SMGs. With the newly available EVLA C-band receivers, it is now possible to search for this emission line in submm galaxies with secure redshifts and previously detected CO line emission. We observe the strongly lensed submm galaxy, SMM J16359+6612 at z=2.5 and the student will lead the data reduction and write-up of this experiment.
The paper has been submitted to the Astronomical Journal for publication.
Marc Eimers, of University of Colorado at Boulder,
worked with Maura McLaughlin and Dunc Lorimer on
140 Foot pulsar observation commissioning
MIT/Lincoln labs in MA is currently using the 140’ telescope in Green Bank, WV to study the Earth’s ionosphere. They are not operating the telescope around the clock however, so astronomers at WVU are working with the NRAO to develop a new data acquisition system to observe pulsars with when the telescope is not being used. My project has been to help with developing and testing this new system. We are using the Parkes Spectrometer, designed by Peter McMahon, as the new pulsar backend for the telescope. One of the first things I did with my advisors, Duncan Lorimer and Maura McLaughlin, was to make a data-taking control graphical user interface to simplify the observation process. We then proceeded to make pulsar timing observations of eight different known pulsars. We began to notice strange behavior in the off-pulse noise levels of the integrated pulse profiles of the different pulsars. We wanted to try and begin to localize the cause of the problems by hooking up an artificial pulsar to the spectrometer. The artificial pulsar machine hadn’t been used in years and it was hard to find anyone who still remembered how to use it, so we documented our testing procedure so that others may refer to it in the future when the machine needs to be used again. Our testing seems to show that the cause of the unexpected behavior in the off pulse noise is not located within the spectrometer itself. However, when the artificial pulse period was set to be very small (on the order or milliseconds) a sort of “bleed-off” feature was seen at the tail end of the pulse. It has yet to be determined whether this is coming from the spectrometer or the artificial pulsar machine itself. The results of the timing observations show that the spectrometer is indeed putting in the correct time stamps. In addition to the timing observations, scintillation observations of the known pulsar B0329+54 were carried out. The diffractive parameters that were calculated from these observations were very questionable, but the length and the center frequency of the observations were less than ideal.
Allison Hammond, of Western Albemarle High School,
worked with Jeff Mangum on
Parent and Daughter Species Evolution in Comet Hale-Bopp
Measurements of the CO, HCN, H2CO, and HCO+ emission distribution from comet Hale-Bopp during perihelion passage in March and April 1997 measured a wide range of emission intensities and distributions. Within these measurements lie clues to the formation and evolution of molecular species in comets, which can lead to information on the constituents of the pre-solar nebula. The analysis of these measurements will result in a better understand of parent and daughter species formation and evolution in comets.
Anthony Hamzeh, of James Madison University,
worked with Tony Remijan on
Probing the Physical and Chemical Properties of Astronomical Environments using Spectral Line Survey
Spectral line surveys provide powerful tools to analyze the coupled dynamical and chemical evolution of molecular clouds. In a survey, many lines of a single species are observed at similar sensitivities, diminishing the errors associated with derived quantities. For example, a particular problem arises in deriving accurate abundances because of overlapping identifications of molecular species. Surveys provide the best means of avoiding this problem by revealing intensity changes in lines of a given species. The student willing to work on this project will investigate the complete 2mm spectral line survey (130-170 GHz) taken with the NRAO 12m telescope between 1993
and 1995 toward the following sources: Sgr B2N, Sgr B2OH, IRC +10 216, Orion (KL), Orion-S, W51M and W3(IRS5). The student will pick one or several of the above sources to further investigate the physical and chemical environments of these very interesting regions and to compare the 12m observations with other published spectral line surveys toward these sources. In addition, the student will have the opportunity to work on a new survey of the Sgr B2N region using the GBT. Overall, the primary goal of the project is to provide the observational constraints for both the physical environment and the complex chemistry, allowing us to investigate the correlations between the physical and chemical evolution of astronomical environments.
Daniel Lacasse, of James Madison University,
worked with Pat Murphy on
Web Image Gallery Refactoring
This project involved participation in updating, modernizing, and
improving of NRAO's Image
Gallery. The current image gallery contains approximately 360
images, with images added weekly, and the subject matter covers such
diverse areas as Astronomy, History, Telescopes, and
Instrumentation.
The migration of the gallery to its own virtual host http://images.nrao.edu/
presented a unique opportunity for study and research into optimal ways
to organize and present both the metadata and the actual images
themselves. Technologies currently in use include the scripting
languages PHP and Perl, and the MySQL
database server, on an Apache/Linux platform.
The main index page was reconstructed to display all thumbnail images
at the same size (100x75 pixels) in a regular grid, for a cleaner
appearance. A technique was developed using the ImageMagick toolset to
re-generate all thumbnails to this size, including optimal cropping.
The Advanced Search option was repaired and enhanced to more
accurately query SIMBAD as needed, to support more user friendly options
and to permit searches with multiple search parameters.
The image submission and approval process was automated and
streamlined. The downloading, naming, resizing and storing of Image
Gallery submissions can now be almost completely automated.
Progress was made on an implementation of image tagging at submission
approval time, using the Astronomy
Visualization Metadata (AVM) Standard which has been documented
by IVOA. Tagging NRAO images in the AVM standard will allow them to
be cataloged and offered through advanced search portals.
Santosh Madhavan, of Lake Highland Preparatory School,
worked with Mark Claussen on
An Archival Study of Maser Sources in IRAS 16293-2422
Maser sources in IRAS 16293-2422 were studied and their flux densities vs LSR velocities were obtained.
Joshua Marvil, of NMT,
worked with Frazer Owen on
Understanding the nature of the microJy radio source population
Josh Marvil, New Mexico Tech continued to work with Jean Eilek and Frazer Owen this summer on a project to understand the nature of the microJy radio source population and the radio-FIR relation. These sources were thought by many to be mostly star-forming galaxies with median luminosities near (or greater than that of Arp220. However, their median size is quite large, > 1" , given their high median redshift ~1. This size corresponds to ~10 kpc, unlike similar local sources whose radio size is < 100pc. We refined our study of the spatial coincidence of the radio and optical emission for the SWIRE deep field and showed that the degree of coincidence depends on radio luminosity. We also studied stacks of the 90cm radio survey in order to estimate the mean spectral indices in subsets selected by radio luminosity and redshift. These same subsets had been studied for FIR luminosity by stacking deep Spitzer MIPS data and classifying each subset as AGN or star-formation driven based on the radio-FIR relation. We found an interesting trend with redshift and AGN vs star-formation for spectral flattening. We spent most of the summer trying to understand this trend. This led to studying various mechanisms for flattening the radio spectrum at low frequencies and how such processes are related to understanding the origin of the radio-FIR correlation.
Stephanie Moats, of New Mexico Tech,
worked with Glen Langston on
GBT searches for new classes of interstellar molecules
Searches for new classes of interstellar molecules will be performed by "folding" of GBT spectra. The broad bandwidth radio spectra will be aligned in velocity and weighted by expected line brightness to achieve optimum sensitivity to new groups of molecules.
The student will help with IDL programming to average spectra; shifting and scaling the data based on chemical models for the expected spectra.
This work is important for studying complex molecule chemistry in the interstellar medium.
Delia Mocanu, of New Mexico Tech,
worked with Bob Garwood on
Design Tool for Display of and Interaction with Large Spectral-Line GBT Data Sets
Instrumentation efforts at the Robert C. Byrd Green Bank Telescope (GBT) are increasingly focused on multi-pixel receivers as well as wide-bandwidth backends for data acquisition, producing large quantities of spectral-line data during an observation. Current GBT data analysis tools lack the ability to display and interact with these large data sets as a whole. For example, viewing large chunks of data simultaneously can be useful in identifying problems in the data (e.g. RFI) as well as discerning structure within the dataset. In this project, the student started by conducting a brief survey of the existing solutions to similar problems at other radio telescopes (e.g. aips++/CASA, JCMT, Arecibo). The student created a prototype tool that does the basic display, zoom and pan, and flag and unflag operations on a GBT dataset.
Bryan Murphy, of Virginia Polytechnic Institute and State University,
worked with Nicole Radziwill on
Applying Semantic Web Technologies and Ontologies to the NRAO Data Vault
The NRAO Data Vault is a web-accessible collection of NRAO science data
from the GBT, VLA and VLBA, which aims to provide convenient access to
browse and download data products which have related keywords which
match a free-text (Google-like) search query. Right now, an astronomer
can search for entries in the Data Vault based on keywords such as
project name, name of the astronomical source, and instrumentation used
to make the observation. This project involves extending the
capabilities of the search function by creating a scheme for records in
the Data Vault to be searched based on "common" categories of
astronomical objects, such as molecular clouds, edge-on and face-on
galaxies, and binary pulsars. Determining which categories are
important by reviewing surveys and the scientific literature, and researching available tools that might be useful in
putting together this project (e.g. Virtual Observatory services) will
be required.
Jeff Paradis, of Rush-Henrietta Senior High School,
worked with Ron Maddalena on
Measuring Atmospheric Refraction at 1GHz Using the NRAO 140’ Telescope
Measuring Atmospheric Refraction at 1GHz Using the NRAO 140’ Telescope
Timothy Pennucci, of Columbia University, Columbia College,
worked with Scott Ransom on
Dynamic Power Spectra: Searching for Compact Binary Pulsars
Some of the most scientifically useful pulsars are those in compact binary orbits (orbital periods Porb < 4-5 hours). Unfortunately, strong Doppler accelerations make finding these pulsars very difficult. One of the more promising techniques to find these objects utilizes Dynamic Power Spectra (DPS), which is sensitive to binary pulsars when the observation length is comparable to the orbital period. We have improved the method by which we create DPS by including a constant frequency derivative acceleration search with interbinning in each DPS segment. We have developed a beta version of a DPS search algorithm that is tuned to find pulsars where the orbital period is approximately equal to the observation duration. We have many terabytes of globular cluster data from the GBT which likely contain unknown compact pulsar binaries. A thorough search of this data in ongoing and if new pulsars are found we will then determine "instant" timing solutions using the archival data.
Brian Sacash, of Ohio Northern University,
worked with Ron DuPlain on
Data Preservation and Access for the NRAO 140ft and 12m Telescopes
In this project, the student will catalog and scientifically characterize the data archives of two retired NRAO single dish telescopes to investigate the tools and techniques of archival research. The NRAO 140 Foot Telescope was completed in the spring of 1965. Located
in Green Bank, West Virginia, the telescope had its last observation run
during the second quarter of 1999. The 12 Meter telescope is located on Kitt Peak, 50 miles west southwest of Tucson, Arizona, and was one of the pioneering instruments in detecting molecules in space. In 2000, the
telescope was closed as an NRAO facility. However, it is currently operating on a temporary basis by Steward Observatory of the University of Arizona. Even though these telescopes are no longer operational, NRAO still has a wealth of data from these two instruments. This project
involves creating a strategy for long-term data curation and access, and
implementing as much of it as possible during the summer session, using
software components already in existence for the NRAO Data Vault and additional software components, as needed, created by the student.
Charli Sakari, of Whitman College,
worked with James Miller-Jones on
Investigating the jets of Cygnus X-3
Cygnus X-3 is one of the brightest X-ray binary sources in the sky,
particularly during its giant outbursts, when it launches relativistic
jets which are seen to evolve on timescales of days. The location of
the core of the binary system has hitherto been uncertain, hindering
the interpretation of the complex morphologies observed in VLBI
observations of the jets. In this project, we have looked at
twenty-three years of archival data on Cygnus X-3 in order to
constrain the proper motion of the system. From that proper motion,
we can now determine the position of the core at any given time. The
radial velocity of the system is unknown, with different authors
deriving very disparate estimates. Using our measured proper motion
and a model of the Galactic potential, we have determined the
three-dimensional space velocities for the full range of radial
velocities proposed in the literature. We use these space velocities
to examine Cygnus X-3's orbital trajectory in the Galaxy, finding a
minimum peculiar velocity of 40km/s. This information can be used to
help constrain whether the system received a natal kick, allowing us
to explore the formation mechanism of the compact object. We also
determined the possible current locations of the supernova in which
the compact object was formed, but current surveys of supernova
remnants and OB associations do not extend far enough from the Sun to
allow us to definitively identify the birthplace of Cygnus X-3.
Alexander Savello, of Emory University,
worked with Robert Dickman on
Kinematic study of Bok globule CB4
Bob Dickman and summer student Alex Savello worked on an analysis of the velocity field of the small, starless Bok globule CB4. Working with Dr. D.C. Lis of Caltech, they completed acquisition of the data in July, and completed a fully-sampled, high velocity resolution map of the cloud in the J=3-2 transition of 13CO using the Caltech Submillimeter Observatory’s 10m radio telescope on Mauna Kea. A map of the globule in the common 12CO isotopic species was also obtained, along with a high quality spectrum of C18O near the cloud center.
Savello completed reducing the data during his summer fellowship. The C18O spectrum affirms the extremely quiescent nature of the gas motions within CB4, and indicates that the adiabatic Mach number is no larger than ~0.5 in the globule’s central regions. A systematic velocity gradient ~ 0.05 km s-1 arcmin-1 consistent with rotation is also present in the cloud. After removing this systematic component, the residual velocity field is found to be remarkably uniform over the cloud.
Matthew Schenker, of Dartmouth College,
worked with Jim Braatz on
Mapping the Megamaser Disk in Mrk 1419
Single-dish observations of the water vapor maser emission from the nucleus of Mrk 1419 reveal a spectrum characteristic of emission from an edge-on accretion disk. Sensitive VLBI observations of such disks can be used in conjunction with spectral line monitoring to determine an angular diameter distance to the host galaxy. The student will reduce a spectral line VLBI observation of the maser in this galaxy to map its structure, for the first time. This galaxy is one of the key sources for the Megamaser Cosmology Project.
Evan Schneider, of Bryn Mawr College,
worked with Scott Ransom on
Searching for the Pulsar in SN1986J
In 1986, a supernova went off in a relatively nearby galaxy and almost certainly produced a neutron star. Over the last 20 years, VLBI observations have shown the expansion of the supernova remnant, and recently, the appearance of what is possibly a pulsar wind nebula in its center. Two years ago we used the GBT to observe SN1986J for 16 hours in order to search for the very young pulsar. The project for this summer was to search these data using a local computer cluster in Charlottesville. Because of the nature of the data, a significant amount of work (involving programming and low-level data analysis) was required to clean the data of interference and other artifacts. Most of this cleaning was done using programs written in python. Once the data was cleaned, two different search methods were used to examine the data: both a singlepulse search, looking for large, extra-bright pulses; and a frequency search, looking for periodic pulses. Although nothing has been found yet, if we do find a pulsar, it will be by far the brightest, most distant, and youngest pulsar known.
Colin Slater, of Case Western Reserve University,
worked with Toney Minter on
Power Spectra of HI in the Outer Galaxy
VLA data have been obtained for several lines of sight toward the outer part of our Galaxy. These data can be used to determine the HI power spectra properties in the outer galaxy. The Canadian Galactic Plane Survey data can also be used to get HI power spectra in the outer Galaxy also. From the HI power spectra the scale on which energy in input into the Interstellar Medium from stellar winds, Supernovae, Galactic rotation, etc. can be determined. It will also be possible to determine the amount of energy input into the turbulence in HI versus Galactic radius. This should allow the separation of the different energy injection processes so that we can identify the dominate process.
Diana Soehl, of Robert Moses Middle School,
worked with Glen Langston on
Detection of Pre-biotic Molecules
Detection of Pre-biotic Molecules
Sarah Streb, of Salpointe Catholic High School,
worked with Miller Goss on
Pulsar Astrometry with the VLA and VLBA and OH Zeeman Pairs in W49 with the VLBA
I did two projects this summer dealing with two separate concepts. The first dealt with accurate pulsar astrometry using in-beam calibrators. My job was to find good in-beam calibrators so that the VLBA could look at them and get highly accurate information about position, size, and brightness. The second project dealt with line of sight OH maser Zeeman pairs in W49. I found several Zeeman pairs and used the frequency shift to determine the line of sight magnetic field at that point. This helps better map the magnetic field around W49 as well as the maser scattering disks and their orientation.
Anthony Woody, of West Virginia University Institute of Technology,
worked with John Ford on
A low EMI m&c interface for the K band Focal Plan Array Receiver
The student would research options for interfacing the proposed K band focal plane array receiver to the monitor and control system. Research topics include characterizing the EMI profile of nano-power microcontrollers, A/D and D/A converters, PC board noise characteristics, and application of the results of this effort to a prototype design for the receiver.