A5032525944- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Astronomy and Astrophysical Research
- Spacecraft and Cryogenic Technologies
- Atomic and Molecular Physics
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Nuclear Physics and Applications
- Advanced Thermodynamic Systems and Engines
- Mass Spectrometry Techniques and Applications
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- History and Developments in Astronomy
- Photocathodes and Microchannel Plates
- Space Exploration and Technology
- Ionosphere and magnetosphere dynamics
- Inorganic Fluorides and Related Compounds
Holy Cross College
2023-2024
University of Illinois Urbana-Champaign
1998-2009
University of Illinois System
1976-2007
National Radio Astronomy Observatory
1975-1988
Max Planck Institute for Radio Astronomy
1985
University of Virginia
1970-1975
Joint Institute for Laboratory Astrophysics
1974
Joint Institute for Nuclear Astrophysics
1974
National Institute of Standards and Technology
1974
University of Colorado Boulder
1974
In 2003, Kuan, Charnley, and co-workers reported the detection of interstellar glycine (NH2CH2COOH) based on observations 27 lines in 19 different spectral bands one or more sources Sgr B2(N-LMH), Orion KL, W51 e1/e2. They supported their report with rotational temperature diagrams for all three sources. this paper, we present essential criteria which can be used a straightforward analysis technique to confirm identity an asymmetric rotor such as glycine. We use new laboratory measurements...
We describe the characteristics of BIMA millimeter wave array at Hat Creek, California. The is an aperture synthesis instrument consisting 9 6-meter diameter antennas which may be deployed in three differenet configurations, with spacings ranging from 7 meters up to 1.3 km. At observing frequency 100 GHz these configurations yield maps angular resolutions 5", 2", and 0.4", over a 2' field. Larger fields mapped by using multiple pointings. For all but oldest telescopes, surface accuracy ≤ 30...
view Abstract Citations (155) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of Possible Maser Emission Near 3.48 Millimeters from an Unidentified Molecular Species in Orion Snyder, L. E. ; Buhl, D. We have detected a group unidentified molecular emission lines near 86,24S MHz ( mm) the direction Nebula cloud. The narrow line widths and compactness region suggest that we observed first millimeter-wave maser. Subject headings: masers...
We previously reported the spectral detection of first interstellar sugar, which is known as glycolaldehyde (CH2OHCHO), by observing six separate millimeter-wave rotational transitions with NRAO 12 m telescope while pointed toward Sagittarius B2 North hot core source Large Molecule Heimat (LMH) source. In present BIMA array work, we have spatially mapped Sgr using 808-717 transition at 82.4 GHz. find that has a spatial scale ≥60'' unlike its isomers methyl formate and acetic acid, are...
We present Berkeley-Maryland-Illlinois Association array observations of formic acid (HCOOH) at 1 mm toward the Orion KL region. Near compact ridge, HCOOH emission is spatially resolved; its partial shell morphology different from that other complex O-bearing molecules such as methyl formate and dimethyl ether. This unique distribution suggests located in a layer delineates interaction region between outflow ambient quiescent gas. also detected hot core. For both cases, ejection grain...
view Abstract Citations (64) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio Detection of Interstellar Dimethyl Ether Snyder, L. E. ; Buhl, D. Schwartz, P. R. Clark, F. O. Johnson, Lovas, J. Giguere, T. dimethyl ether, (CH3)2O, has been detected in emission from the direction Orion Nebula molecular cloud. The observed velocity 6 H 515 transition at 90.9 GHz is excellent agreement with other molecules toward Orion. Observations 2 86.2 and...
view Abstract Citations (80) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio detection of interstellar sulfur dioxide. Snyder, L. E. ; Hollis, J. M. Ulich, B. Lovas, F. Johnson, D. R. Buhl, Interstellar dioxide (SO2) has been detected in emission from the direction Orion Nebula molecular cloud and Sgr B2. SO2 is heaviest molecule to date, only nonlinear triatomic which does not contain hydrogen. The remarkable profiles suggest that two...
We have surveyed 12 Galactic hot molecular cores for interstellar acetic acid (CH3COOH). This is the most extensive search to date. detected a new source of toward high-mass core G34.3+0.2. Using temperature range between 70 and 185 K, we find CH3COOH column density (0.77-1.64) × 1015 cm-2 gives relative CH3COOH/HCOOCH3 abundance ratio ~3.3 10-2, which comparable (3-6) 10-2 found Sgr B2(N-LMH) W51e2 by Remijan colleagues. All currently known sources are within 7 kpc center. Furthermore, our...
We have detected interstellar acetic acid (CH3COOH) toward the hot core source W51e2. This is first new of CH3COOH since its discovery by Mehringer et al. Sgr B2(N-LMH). In this paper, we report observations at two frequencies B2(N-LMH) with OVRO array and 10 W51e2 Berkeley-Illinois-Maryland Association array. Toward agreement in positions, intensities, velocities between lines from previous study strongly indicates that all four are coming a common source. Using transitions, find an average...
We have detected strong methyl cyanide (CH3CN) emission lines from the hot core regions W51e1 and W51e2, using BIMA Array. This is first survey of CH3CN toward W51 to utilize both 3 mm (J = 5-4 6-5) 1 12-11, 13-12, 14-13) transitions as probes physical chemical conditions present in these regions. The reveals molecular clumps centered on ultracompact H II found by Zhang colleagues. show large optical depths lower K W51. To determine true kinetic temperatures, densities, column densities...
We present high resolution, Combined Array for Research in Millimeter-Wave Astronomy (CARMA), $λ$=1mm observations of several molecular species toward Orion-KL. These are the highest spatial and spectral resolution 1mm these molecules to date. Our show that ethyl cyanide [C$_2$H$_5$CN] vinyl [C$_2$H$_3$CN] originate from multiple cores near Orion hot core IRc7. Additionally we dimethyl ether [(CH$_3$)$_2$O] methyl formate [HCOOCH$_3$] IRc5 IRc6 acetone [(CH$_3$)$_2$CO] originates only areas...
view Abstract Citations (48) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A search for the lowest-energy conformer of interstellar glycine Hollis, J. M. ; Snyder, L. E. Suenram, R. D. Lovas, F. The first conformation has been carried out. An emission line detected in Sgr B2 which is coincident frequency with J(K-K+) = 14(1, 14)-13(1, 13) transition I glycine; while carrier observed uncertain, no other frequency-coincident species are known,...
view Abstract Citations (88) References (231) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Recommended rest frequencies for observed interstellar molecular transitions Lovas, F. J. ; Johnson, D. R. Snyder, L. E. The most accurate values presently available the of all known are presented and recommended reference in future astronomical observations radio microwave regions. have been carefully selected after critical evaluation spectroscopic literature....
view Abstract Citations (49) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio detection of the interstellar formyl radical. Snyder, L. E. ; Hollis, J. M. Ulich, B. The radical, HCO, has been detected in molecular clouds through strongest hyperfine component one its microwave transitions. this molecule apparently is consistent with extensions ion-molecule formation theory which deal moderately dense where both ionized carbon and monoxide...
view Abstract Citations (55) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of Interstellar N 2O: A New Molecule Containing an N-O Bond Ziurys, L. M. ; Apponi, A. J. Hollis, Snyder, E. new interstellar molecule, N2O, known as nitrous oxide or 'laughing gas,' has been detected using the NRAO 12 m telescope. The J = 3 - 2, 4 3, 5 4, and 6 rotational transitions this species at 75, 100, 125, 150 GHz, respectively, were observed toward...
We have conducted a deep Q-band (λ ~ 7 mm) search with the Very Large Array (VLA) toward OMC-1 for lowest energy conformation (conformer I) of glycine (NH2CH2COOH) in four rotational transitions: 615-514, 624-523, 717-616, and 707-606. Our VLA observations sample smallest scale structures to date OMC-1. No emission features were detected. Thus, if exists OMC-1, it is below our detection limit, or more spatially extended than other large molecules this source, primarily its high-energy form...
We have surveyed the high-mass Galactic star-forming regions G19.61-0.23, G45.47+0.05, and W75N for interstellar methanol (CH3OH), formic acid (HCOOH), acetic (CH3COOH), methyl formate (HCOOCH3), cyanide (CH3CN), ethyl (CH3CH2CN) with Berkeley-Illinois-Maryland Association Array. From our observations, we detected two new sources of HCOOH toward hot core G19.61-0.23 W75N. also made first detections CH3CH2CN HCOOCH3 G19.61-0.23. The relative HCOOH/HCOOCH3 abundance ratio is 0.18, which...
The J(K-1 K1) = -1(11) -10(10) transition of H2CO was detected in emission at 4829.659 MHz from Comet Halley. line had a peak intensity 2.66 + or - 0.78 mJy/beam with small blueshift -0.76 0.40 km/s, which is consistent the anisotropic outgassing nucleus solar direction found for other cometary species. Data analysis suggests that produced an extended source coma as well directly and it not refrigerated interstellar dark nebulae. derived production rate 1.5 x 10 to 28th molecules/s obtained...
Interstellar cyanoallene (CH2CCHCN) has been detected with the 100 m Green Bank Telescope (GBT) toward dark Taurus molecular cloud (TMC-1) by means of 414-313, 404-303, 515-414, and 505-404 rotational transitions at 20.2, 20.6, 25.2, 25.7 GHz, respectively. The hyperfine structure (hfs) 414-313 transition is resolved; remaining have hfs components that are blended but inferred owing to line width excesses atypical TMC-1. An analysis these four yields an average column density NT = 2.0(5) ×...
view Abstract Citations (43) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An extensive galactic search for conformer II Glycine. Snyder, L. E. ; Hollis, J. M. Suenram, R. D. Lovas, F. Brown, W. Buhl, The most reported to date glycine, a higher energy form of the simplest amino acid has been conducted. utilized four glycine transitions at centimeter wavelengths and 21 millimeter observe 18 molecular sources one comet. No lines were detected,...
view Abstract Citations (44) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio detection of nitroxyl (HNO): the first interstellar NO bond. Ulich, B. L. ; Hollis, J. M. Snyder, E. A spectral line identified as J(K- K+) = 1(01)-0(00) transition has been detected in emission from directions Sgr B2 and NGC 2024. An abundance ratio carbon to nitrogen about 1.4 is derived for 2024, which suggests that may be abundant molecular clouds. Detection...