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Related papers: [CII] observations of H$_2$ molecular layers in tr…

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The properties of molecular clouds associated with 10 HII regions were studied using CO observations. We identified 142 dense clumps within our sample and found that our sources are divided into two categories: those with clumps that show a…

Solar and Stellar Astrophysics · Physics 2015-05-27 Mohaddesseh Azimlu , Michel Fich

The [CII] fine-structure transition at 158 micron is frequently the brightest far-infrared line in galaxies. Due to its low ionization potential, C+ can trace the ionized, atomic, and molecular phases of the ISM. We present velocity…

Far-infrared molecular emission is an important tool used to understand the excitation mechanisms of the gas in the inter-stellar medium of star-forming galaxies. In the present work, we model the emission from rotational transitions with…

Astrophysics of Galaxies · Physics 2016-11-23 M. V. Kazandjian , I. Pelupessy , R. Meijerink , F. P. Israel , C. M. Coppola , M. J. F. Rosenberg , M. Spaans

Ionized carbon is the main gas-phase reservoir of carbon in the neutral diffuse interstellar medium and its 158 micron fine structure transition [CII] is the most important cooling line of the diffuse interstellar medium (ISM). We combine…

We have determined column densities of H I and/or H_2 for sight lines in the Magellanic Clouds from archival HST and FUSE spectra of H I Lyman-alpha and H_2 Lyman-band absorption. Together with some similar data from the literature, we now…

Astrophysics of Galaxies · Physics 2015-06-03 Daniel E. Welty , Rui Xue , Tony Wong

We know little about the outermost portions of galaxies because there is little light coming from them. We do know that in many cases atomic hydrogen (HI) extends well beyond the optical radius \cite{Casertano91}. In the centers of…

Astrophysics · Physics 2009-11-10 Jonathan Braine , Fabrice Herpin

$Aims.$ We characterize the molecular-line emission of three clouds whose star-formation rates span one order of magnitude: California, Perseus, and Orion A. $Methods.$ We use stratified random sampling to select positions representing the…

Astrophysics of Galaxies · Physics 2023-11-29 M. Tafalla , A. Usero , A. Hacar

Large scale mapping observations of the 3P1-3P0 fine structure transition of atomic carbon (CI, 492 GHz) and the J=3-2 transition of CO (346 GHz) toward the Orion A molecular cloud have been carried out with the Mt. Fuji submillimeter-wave…

We present a measurement of the mean density profile of Ca II gas around galaxies out to ~ 200 kpc, traced by Fraunhofer's H & K absorption lines. The measurement is based on cross-correlating the positions of about one million foreground…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Guangtun Zhu , Brice Ménard

We have detected the v=1-0 S(1) (2.1218 um) and v=2-1 S(1) (2.2477 um) lines of H_2 in the Galactic centre, in a 90 x 27 arcsec region between the northeastern boundary of the non-thermal source, Sgr A East, and the giant molecular cloud…

This work presents high spectral resolution observations of the \CII\ line at 158 \micron, one of the major cooling lines of the interstellar medium, taken with the HIFI heterodyne spectrometer on the Herschel satellite. In BCLMP 691, an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 J. Braine , P. Gratier , C. Kramer , F. P. Israel , F. van der Tak , B. Mookerjea , M. Boquien , F. Tabatabaei , P. van der Werf , C. Henkel

Analyzing the Galactic plane CO survey with the Nobeyama 45-m telescope, we compared the spectral column density (SCD) of H$_2$ calculated for $^{12}$CO line using the current conversion factor $X_{\rm CO}$ to that for $^{13}$CO line under…

Astrophysics of Galaxies · Physics 2020-07-22 Yoshiaki Sofue , Mikito Kohno

Up to now, mostly relatively simple molecules have been detected in interstellar diffuse molecular clouds in our galaxy, but more complex species have been reported in the diffuse/translucent medium of a z = 0.89 spiral galaxy. We aim at…

Astrophysics of Galaxies · Physics 2017-09-20 V. Thiel , A. Belloche , K. M. Menten , R. T. Garrod , H. S. P. Müller

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…

Astrophysics · Physics 2009-10-30 Marco Spaans , David A. Neufeld

The Small Magellanic Cloud (SMC) provides the only laboratory to study the structure of molecular gas at high resolution and low metallicity. We present results from the Herschel Spectroscopic Survey of the SMC (HS$^{3}$), which mapped the…

(ABRIDGED) We present a Far-Ultraviolet Spectroscopic Explorer survey of highly ionized high-velocity clouds (HVCs) in 66 extragalactic sight lines. We find a total of 63 high-velocity O VI absorbers, 16 with 21 cm-emitting H I counterparts…

Astrophysics · Physics 2009-11-11 Andrew J. Fox , Blair D. Savage , Bart P. Wakker

We made CO(1-0) observations of 103 lines of sight in the core and envelope of the high-latitude cloud MBM 40 to determine how the CO-H_2 conversion factor (X_CO) varies throughout the cloud. Calibrating X_CO with CH data at similar…

Astrophysics of Galaxies · Physics 2015-06-16 David L. Cotten , Loris Magnani

Seven isolated, nearby low-mass starless molecular cloud cores have been observed as part of the Herschel key program Earliest Phases of Star formation (EPoS). By applying a ray-tracing technique to the obtained continuum emission and…

Methods: 12CO emission is imaged in position and position-velocity space analyzed statistically, and then compared with maps of total reddening and with models of the C+ - CO transition in H2-bearing diffuse clouds. Results: Around Zeta…

Astrophysics of Galaxies · Physics 2015-05-13 H. S. Liszt , J. Pety , K. Tachihara

High-velocity clouds (HVC), fast-moving ionized and neutral gas clouds found at high galactic latitudes, may play an important role in the evolution of the Milky Way. The extent of this role depends sensitively on their distances and total…

Astrophysics of Galaxies · Physics 2015-06-04 N. Lehner , J. C. Howk , C. Thom , A. J. Fox , J. Tumlinson , T. M. Tripp , J. D. Meiring