Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 16 of 16
Full-Text Articles in Physical Sciences and Mathematics
Swas Observations Of Water In Molecular Outflows, J Franklin, Ronald L. Snell, Mj Kaufman, Gj Melnick, Da Neufeld, Dj Hollenbach, Ea Bergin
Swas Observations Of Water In Molecular Outflows, J Franklin, Ronald L. Snell, Mj Kaufman, Gj Melnick, Da Neufeld, Dj Hollenbach, Ea Bergin
Astronomy Department Faculty Publication Series
We present detections of the ground-state 110→ 101 transition of ortho-H2O at 557 GHz in 18 molecular outflows based on data from the Submillimeter Wave Astronomy Satellite (SWAS). These results are combined with ground-based observations of the J = 1–0 transitions of 12CO and 13CO obtained at the Five College Radio Astronomy Observatory (FCRAO). Data from Infrared Space Observatory (ISO) for a subset of the outflows are also discussed. Assuming that the SWAS water-line emission originates from the same gas traced by CO emission, we find that the outflowing …
The Five College Radio Astronomy Observatory Co Mapping Survey Of The Taurus Molecular Cloud, Gopal Narayanan, Mh Heyer, C Brunt, Pf Goldsmith, Ronald L. Snell, D Li
The Five College Radio Astronomy Observatory Co Mapping Survey Of The Taurus Molecular Cloud, Gopal Narayanan, Mh Heyer, C Brunt, Pf Goldsmith, Ronald L. Snell, D Li
Astronomy Department Faculty Publication Series
The FCRAO Survey of the Taurus molecular cloud observed the 12CO and 13CO J = 1–0 emission from 98 deg2 of this important, nearby, star-forming region. This set of data with 45'' resolution comprises the highest spatial dynamic range image of an individual molecular cloud constructed to date and provides valuable insights to the molecular gas distribution, kinematics, and the star formation process. In this contribution, we describe the observations, calibration, data processing, and characteristics of the noise and line emission of the survey. The angular distribution of 12CO and 13CO emission over 1 km …
Large-Scale Structure Of The Molecular Gas In Taurus Revealed By High Linear Dynamic Range Spectral Line Mapping, Pf Goldsmith, M Heyer, Gopal Narayanan, Ronald L. Snell, D Li, C Brunt
Large-Scale Structure Of The Molecular Gas In Taurus Revealed By High Linear Dynamic Range Spectral Line Mapping, Pf Goldsmith, M Heyer, Gopal Narayanan, Ronald L. Snell, D Li, C Brunt
Astronomy Department Faculty Publication Series
We report the results of a 100 deg2 survey of the Taurus molecular cloud region in 12CO and 13CO J = 1→ 0. The image of the cloud in each velocity channel includes 3 × 106 Nyquist-sampled pixels on a 20'' grid. The high sensitivity and large spatial dynamic range of the maps reveal a very complex, highly structured cloud morphology, including filaments, cavities, and rings. The axes of the striations seen in the 12CO emission from relatively diffuse gas are aligned with the direction of the magnetic field. We have developed a statistical …
Warm Molecular Hydrogen In The Spitzer Sings Galaxy Sample, H Roussel, G Helou, Dj Hollenbach, Bt Draine, Jd Smith, L Armus, E Schinnerer, F Walter, Cw Engelbracht, Md Thornley, Rc Kennicutt, D Calzetti, Da Dale, Ej Murphy, C Bot
Warm Molecular Hydrogen In The Spitzer Sings Galaxy Sample, H Roussel, G Helou, Dj Hollenbach, Bt Draine, Jd Smith, L Armus, E Schinnerer, F Walter, Cw Engelbracht, Md Thornley, Rc Kennicutt, D Calzetti, Da Dale, Ej Murphy, C Bot
Astronomy Department Faculty Publication Series
Results on the properties of warm molecular hydrogen in 57 normal galaxies are derived from measurements of H2 rotational transitions, obtained as part of SINGS. This study extends previous extragalactic surveys of emission lines of H2 to fainter and more common systems (LFIR = 107-6 × 1010 L). The 17 μm S(1) transition is securely detected in the nuclear regions of 86% of galaxies with stellar masses above 109.5 M. The derived column densities of warm H2 (T ≥ 100 K), although averaged over kiloparsec-scale areas, are commensurate with values observed in resolved photodissociation regions. They amount to between 1% …
Spitzer Spectral Line Mapping Of Supernova Remnants. I. Basic Data And Principal Component Analysis, Da Neufeld, Dj Hollenbach, Mj Kaufman, Ronald L. Snell, Gj Melnick, Ea Bergin, P Sonnentrucker
Spitzer Spectral Line Mapping Of Supernova Remnants. I. Basic Data And Principal Component Analysis, Da Neufeld, Dj Hollenbach, Mj Kaufman, Ronald L. Snell, Gj Melnick, Ea Bergin, P Sonnentrucker
Astronomy Department Faculty Publication Series
We report the results of spectroscopic mapping observations carried out toward small (1' × 1') regions within the supernova remnants W44, W28, IC 443, and 3C 391 using the Infrared Spectrograph (IRS) of the Spitzer Space Telescope. These observations, covering the 5.2-37 μm spectral region, have led to the detection of a total of 15 fine-structure transitions of Ne+, Ne++, Si+, P+, S, S++, Cl+, Fe+, and Fe++; the S(0)-S(7) pure rotational lines of molecular hydrogen; and the R(3) …
Spitzer Observations Of Hydrogen Deuteride, Da Neufeld, Jd Green, Dj Hollenbach, P Sonnentrucker, Gj Melnick, Ea Bergin, Ronald L. Snell, Wj Forrest, Dm Watson, Mj Kaufman
Spitzer Observations Of Hydrogen Deuteride, Da Neufeld, Jd Green, Dj Hollenbach, P Sonnentrucker, Gj Melnick, Ea Bergin, Ronald L. Snell, Wj Forrest, Dm Watson, Mj Kaufman
Astronomy Department Faculty Publication Series
No abstract provided.
Water Absorption From Line-Of-Sight Clouds Toward W49a, R Plume, Mj Kaufman, Da Neufeld, Ronald L. Snell, Dj Hollenbach, Pf Goldsmith, J Howe, Ea Bergin, Gj Melnick, F Bensch
Water Absorption From Line-Of-Sight Clouds Toward W49a, R Plume, Mj Kaufman, Da Neufeld, Ronald L. Snell, Dj Hollenbach, Pf Goldsmith, J Howe, Ea Bergin, Gj Melnick, F Bensch
Astronomy Department Faculty Publication Series
We have observed six clouds along the line of sight toward W49A using the Submillimeter Wave Astronomy Satellite and several ground-based observatories. The ortho-H2O 110 → 101 and OH (1665 and 1667 MHz) transitions are observed in absorption, whereas the low-J CO, 13CO, and C18O lines, as well as the [C I] 3P1-3P0 transition, are seen in emission. The emission lines allow us to determine the gas density (n ~ 1500-3000 cm-3) and CO column densities [N(CO) ~ 7.9 …
A Survey Of 557 Ghz Water Vapor Emission In The Ngc 1333 Molecular Cloud, Ea Bergin, Mj Kaufman, Gj Melnick, Ronald L. Snell, Je Howe
A Survey Of 557 Ghz Water Vapor Emission In The Ngc 1333 Molecular Cloud, Ea Bergin, Mj Kaufman, Gj Melnick, Ronald L. Snell, Je Howe
Astronomy Department Faculty Publication Series
Using NASA's Submillimeter Wave Astronomy Satellite (SWAS), we have examined the production of water in quiescent and shocked molecular gas through a survey of the 556.936 GHz 110-101 transition of ortho-H2O in the NGC 1333 molecular core. These observations reveal broad emission lines associated with the IRAS 2, IRAS 4, IRAS 7, and HH 7-11 outflows. Toward three positions we detect narrow (Δv ~ 2-3 km s-1) emission lines clearly associated with the ambient gas. The SWAS observations, with a resolution of ~4', are supplemented with observations from the Infrared …
Star Formation In Bright-Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Ch De Vries, Gopal Narayanan, Ronald L. Snell
Star Formation In Bright-Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Ch De Vries, Gopal Narayanan, Ronald L. Snell
Astronomy Department Faculty Publication Series
We present the results of the first detailed millimeter and submillimeter molecular line survey of bright-rimmed clouds, observed at FCRAO in the CO (J = 1 → 0), C18O (J = 1 → 0), HCO+ (J = 1 → 0), H13CO+ (J = 1 → 0), and N2H+ (J = 1 → 0) transitions, and at the Heinrich Hertz Telescope in the CO (J = 2 → 1), HCO+ (J = 3 → 2), HCO+ (J = 4 → 3), H …
Sensitive Limits On The Water Abundance In Cold Low-Mass Molecular Cores, Ea Bergin, Ronald L. Snell
Sensitive Limits On The Water Abundance In Cold Low-Mass Molecular Cores, Ea Bergin, Ronald L. Snell
Astronomy Department Faculty Publication Series
We present Submillimeter Wave Astronomy Satellite observations of water vapor in two cold starless clouds, B68 and core D in ρ Ophiuchi. Sensitive nondetections of the 110-101 transition of o-H2O are reported for each source. Both molecular cores have been previously examined by detailed observations that have characterized the physical structure. Using these rather well-defined physical properties and a Monte Carlo radiation transfer model, we have removed one of the largest uncertainties from the abundance calculation and set the lowest water abundance limit to date in cold low-mass molecular cores. These limits are x(o-H …
The Equilibrium State Of Molecular Regions In The Outer Galaxy, Mh Heyer, Jm Carpenter, Ronald L. Snell
The Equilibrium State Of Molecular Regions In The Outer Galaxy, Mh Heyer, Jm Carpenter, Ronald L. Snell
Astronomy Department Faculty Publication Series
A summary of global properties and an evaluation of the equilibrium state of molecular regions in the outer Galaxy are presented from the decomposition of the FCRAO Outer Galaxy Survey and targeted 12CO and 13CO observations of four giant molecular cloud complexes. The ensemble of identified objects includes both small, isolated clouds and clumps within larger cloud complexes. The 12CO luminosity function and size distribution of a subsample of objects with well-defined distances are determined such that ΔN/ΔLCO = L and ΔN/Δre = r. 12CO velocity dispersions …
Submillimeter Wave Astronomy Satellite Observations Of Extended Water Emission In Orion, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Submillimeter Wave Astronomy Satellite Observations Of Extended Water Emission In Orion, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Astronomy Department Faculty Publication Series
We have used the Submillimeter Wave Astronomy Satellite to map the ground-state 110 → 101 transition of ortho-H2O at 557 GHz in the Orion molecular cloud. H2O emission was detected in Orion over an angular extent of about 20', or nearly 3 pc. The water emission is relatively weak, with line widths (3-6 km s-1) and VLSR velocities (9-11 km s-1) consistent with an origin in the cold gas of the molecular ridge. We find that the ortho-H2O abundance relative to H2 in the extended gas …
Water Abundance In Molecular Cloud Cores, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Water Abundance In Molecular Cloud Cores, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Astronomy Department Faculty Publication Series
We present Submillimeter Wave Astronomy Satellite (SWAS) observations of the 110 → 101 transition of ortho-H2O at 557 GHz toward 12 molecular cloud cores. The water emission was detected in NGC 7538, ρ Oph A, NGC 2024, CRL 2591, W3, W3OH, Mon R2, and W33 and was not detected in TMC-1, L134N, and B335. We also present a small map of the H2O emission in S140. Observations of the H218O line were obtained toward S140 and NGC 7538, but no emission was detected. The abundance of ortho-H2O …
The Distribution Of Water Emission In M17sw, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
The Distribution Of Water Emission In M17sw, Ronald L. Snell, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Astronomy Department Faculty Publication Series
We present a 17-point map of the M17SW cloud core in the 110 → 101 transition of ortho-H2O at 557 GHz obtained with Submillimeter Wave Astronomy Satellite. Water emission was detected in 11 of the 17 observed positions. The line widths of the H2O emission vary between 4 and 9 km s-1 and are similar to other emission lines that arise in the M17SW core. A direct comparison is made between the spatial extent of the H2O emission and the 13CO J = 5 → 4 emission; the good …
Extended [C I] And (Co)-C-13 (5 -> 4) Emission In M17sw, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Dj Hollenbach, Mj Kaufman, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Ronald L. Snell, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Extended [C I] And (Co)-C-13 (5 -> 4) Emission In M17sw, Je Howe, Mln Ashby, Ea Bergin, G Chin, Nr Erickson, Pf Goldsmith, M Harwit, Dj Hollenbach, Mj Kaufman, Sc Kleiner, Dg Koch, Da Neufeld, Bm Patten, R Plume, R Schieder, Ronald L. Snell, Jr Stauffer, V Tolls, Z Wang, G Winnewisser, Yf Zhang, Gj Melnick
Astronomy Department Faculty Publication Series
We mapped a 13 × 22 pc region in emission from 492 GHz [C I] and, for the first time, 551 GHz 13CO (5 → 4) in the giant molecular cloud M17SW. The morphologies of the [C I] and 13CO emission are strikingly similar. The extent and intensity of the [C I] and 13CO (5 → 4) emission is explained as arising from photodissociation regions on the surfaces of embedded molecular clumps. Modeling of the 13CO (5 → 4) emission in comparison to 13CO (1 → 0) indicates a temperature gradient across the cloud, peaking …
Origin And Evolution Of The Cepheus Bubble, Na Patel, Pf Goldsmith, Mh Heyer, Rl Snell, P Pratap
Origin And Evolution Of The Cepheus Bubble, Na Patel, Pf Goldsmith, Mh Heyer, Rl Snell, P Pratap
Astronomy Department Faculty Publication Series
We have imaged a 10° × 10° region of the Cepheus bubble in the J = 1-0 line of CO and the 21 cm line of atomic hydrogen. The CO emission defines a giant expanding shell 120 pc in diameter, which is similar to that seen in the IRAS sky maps. We estimate the total gas mass in the region to be ~4 × 105M☉. The total kinetic energy from the observed spread of velocities of the molecular clouds is ~1051ergs. We suggest that the members of earlier generations of massive stars in NGC 7160 are responsible for …