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200 papers

The diffuse interstellar medium is dynamic, and its chemistry and evolution is determined by shock fronts as well as photodissociation. Shocks are implied by the supersonic motions and velocity dispersion often statistically called…

Astrophysics of Galaxies · Physics 2021-03-17 William T. Reach , Carl Heiles

Using the Plateau de Bure interferometer, we observed the 3mm absorption lines of CN, HCN and HNC from some of the diffuse clouds which lie toward our well-studied sample of compact extragalactic mm-wave continuum sources. The column…

Astrophysics · Physics 2009-11-06 H. Liszt , R. Lucas

We combine Herschel observations of a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the…

Astrophysics of Galaxies · Physics 2015-06-11 P. Sonnentrucker , M. Wolfire , D. A. Neufeld , N. Flagey , M. Gerin , P. Goldsmith , D. Lis , R. Monje

Context. Infrared dark clouds (IRDCs) are ubiquitous in the Milky Way, yet they play a crucial role in breeding newly-formed stars. Aims. With the aim of further understanding the dynamics, chemistry, and evolution of IRDCs, we carried out…

Astrophysics of Galaxies · Physics 2017-02-08 Chuan-Peng Zhang , Jing-Hua Yuan , Guang-Xing Li , Jian-Jun Zhou , Jun-Jie Wang

We present a millimeter wave study of a cluster of bipolar CO outflows embedded in the western end of the Circinus molecular cloud complex, G317-4, that is traced by very high optical extinction. For an assumed distance of 700 pc, the…

Astrophysics · Physics 2014-10-13 John Bally , Bo Reipurth , Charles J. Lada , Youssef Billawala

We present ISO observations of several H2 pure-rotational lines (from S(0) to S(5)) towards a sample of 16 molecular clouds distributed along the central ~ 500 pc of the Galaxy. We also present C18O and 13CO J=1->0 and J=2->1 observations…

We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusually large velocity dispersions of more than 100 km/s (FWHM)…

Astrophysics · Physics 2015-06-24 Harald Riffert , Pawan Kumar , W. K. Huchtmeier

We have mapped the dust continuum emission from the molecular cloud covering a region of 28pcx94pc associated with the well-known HII region RCW 106 at 1.2 mm using SIMBA on SEST. The observations, having an HPBW of 24" (0.4 pc), reveal 95…

Astrophysics · Physics 2009-11-10 B. Mookerjea , C. Kramer , M. Nielbock , L. -A. Nyman

We report an upper limit of 9 x 10^{12} cm-2 on the column density of water in the translucent cloud along the line of sight toward HD 154368. This result is based upon a search for the C-X band of water near 1240 \AA carried out using the…

Astrophysics · Physics 2009-10-30 Marco Spaans , David Neufeld , Stephen Lepp , Gary J. Melnick , John Stauffer

Until now the known sources in the Galactic center with sufficiently smooth spectra and of sufficient brightness to be suitable for high resolution infrared absorption spectroscopy of interstellar gas occupied a narrow range of longitudes,…

Astrophysics of Galaxies · Physics 2015-05-14 T. R. Geballe , T. Oka

Context. The earliest phases of high-mass star formation are poorly understood. Aims. Our goal is to determine the physical conditions and kinematic structure of massive star-forming cloud clumps. Methods. We analyze H$_2$O 557 GHz line…

Solar and Stellar Astrophysics · Physics 2014-10-15 Russell F. Shipman , Floris F. S van der Tak , Friedrich Wyrowski , Fabrice Herpin , Wilfred Frieswijk

The Perseus molecular cloud complex is a ~30pc long chain of molecular clouds most well-known for the two star-forming clusters NGC1333 and IC348 and the well-studied outflow source in B5. However, when studied at mid- to far-infrared…

Astrophysics · Physics 2009-11-11 Naomi A. Ridge , Scott L. Schnee , Alyssa A. Goodman , Jonathan B. Foster

We present J, H and K-band spectroscopy of Cygnus A, spanning 1.0-2.4 micron in the rest-frame and hence several rovibrational H2, H recombination and [FeII] emission lines. The lines are spatially extended by up to 6kpc from the nucleus,…

Astrophysics · Physics 2016-08-30 R. J. Wilman , A. C. Edge , R. M. Johnstone , C. S. Crawford , A. C. Fabian

We extend the analytic theory presented by Sternberg et al. (2014) and Bialy & Sternberg (2016) for the production of atomic hydrogen (HI) via FUV photodissociation at the boundaries of dense interstellar molecular (H$_2$) clouds, to also…

Astrophysics of Galaxies · Physics 2023-10-18 Amiel Sternberg , Shmuel Bialy , Alon Gurman

We present high-resolution (FWHM ~ 0.3-1.5 km/s) spectra of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species -- for individual components identified in the…

Astrophysics · Physics 2009-11-07 Daniel E. Welty , L. M. Hobbs , Donald C. Morton

Cold atomic hydrogen clouds are the precursors of molecular clouds. Due to self-absorption, the opacity of cold atomic hydrogen may be high, and this gas may constitute an important mass component of the interstellar medium (ISM). Atomic…

Astrophysics of Galaxies · Physics 2020-01-08 Boyang Liu , Di Li , Lister Staveley-Smith , Lei Qian , Tony Wong , Paul Goldsmith

We have conducted a survey of Ultra-luminous Infrared Galaxies (ULIRGs) with the Infrared Spectrograph on the Spitzer Space Telescope, obtaining spectra from 5.0-38.5um for 77 sources with 0.02<z <0.93. Observations of the pure rotational…

Astrophysics · Physics 2009-11-11 S. J. U. Higdon , L. Armus , J. L. Higdon , B. T. Soifer , H. W. W. Spoon

We derive the molecular properties for a sample of 301 Galactic HII regions including 123 ultra compact (UC), 105 compact, and 73 diffuse nebulae. We analyze all sources within the BU-FCRAO Galactic Ring Survey (GRS) of 13CO emission known…

We have obtained column density maps for an unbiased sample of 120 molecular clouds in the third quadrant of the Milky Way mid-plane (b$\le |5|^{\circ}$) within the galactic longitude range from 195$^{\circ}$ to 225$^{\circ}$, using the…

Astrophysics of Galaxies · Physics 2022-08-31 Yuehui Ma , Hongchi Wang , Miaomiao Zhang , Chen Wang , Shaobo Zhang , Yao Liu , Chong Li , Yuqing Zheng , Lixia Yuan , Ji Yang

We report interstellar C II column densities or upper limits determined from weak absorption of the 2325.4029 A intersystem transition observed in six translucent sightlines with STIS. The sightlines sample a wide range of interstellar…

Astrophysics · Physics 2009-11-10 U. J. Sofia , J. T. Lauroesch , D. M. Meyer , S. I. B. Cartledge