Molecular Hydrogen Absorption Line Detected in Dense Molecular Clouds

2006 ◽  
pp. 248-251
Author(s):  
Tomonori Usuda ◽  
Miwa Goto
Keyword(s):  
Absorption Line ◽  
Molecular Hydrogen ◽  
Hydrogen Absorption ◽  
Molecular Clouds

scholarly journals HST /COS SPECTRA OF DF Tau AND V4046 Sgr: FIRST DETECTION OF MOLECULAR HYDROGEN ABSORPTION AGAINST THE Lyα EMISSION LINE

2011 ◽  
Vol 730 (1) ◽  
pp. L10 ◽  
Author(s):  
Hao Yang ◽  
Jeffrey L. Linsky ◽  
Kevin France
Keyword(s):  
Emission Line ◽  
Molecular Hydrogen ◽  
Hydrogen Absorption

scholarly journals High-Redshift Molecular Clouds and Absorption-Line Spectra of Quasars

1983 ◽  
Vol 104 ◽  
pp. 365-366
Author(s):  
D. A. Varshalovich ◽  
S. A. Levshakov
Keyword(s):  
Absorption Line ◽  
Molecular Clouds ◽  
High Redshift ◽  
Optical Spectra ◽  
Molecular Lines

The optical spectra of distant quasars (OQ 172, PHL 957, PKS 0237–233 and 11 others) were reanalysed with the purpose of searching molecular lines /2, 4/.

scholarly journals Molecular gas in the Small Magellanic Cloud

1991 ◽  
Vol 148 ◽  
pp. 429-430
Author(s):  
Monica Rubio
Keyword(s):  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Column Density ◽  
Angular Resolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Molecular Gas ◽  
Small Magellanic Cloud ◽  
Hydrogen Column Density ◽  
Co Emission

We summarize the results of observations of molecular gas from the Small Magellanic Cloud (SMC) made with low angular resolution (8'.8). These observations show that the CO emission is weak (TA˜ 0.04K) and that the CO luminosities of the Clouds are low compared to those of Galactic molecular clouds. The factor to convert the CO luminosity to molecular hydrogen column density for the SMC is ˜20 and three times larger than those derived for clouds in our Galaxy and in the Large Magellanic Cloud (LMC) respectively. In addition, we present preliminary results of high resolution (40″) observations of SMC molecular clouds made with the SEST telescope.

scholarly journals Formation, Evolution and Destruction of Possible DIB Carriers: Dirty Molecular Hydrogen Ice Clusters

2013 ◽  
Vol 9 (S297) ◽  
pp. 381-382
Author(s):  
D. K. Lynch ◽  
L. S. Bernstein ◽  
F. O. Clark
Keyword(s):  
Interstellar Medium ◽  
Single Molecule ◽  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Single Layer ◽  
Molecular Clusters ◽  
Electronic Transitions ◽  
Giant Molecular Clouds ◽  
Diffuse Interstellar Bands ◽  
Optical Photons

AbstractWe suggest that the diffuse interstellar bands (DIBs) are absorption lines arising from electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion (“seed”), embedded in a single-layer shell of H2 molecules (Bernstein et al. 2013). We refer to these clusters as CHCs (Contaminated H2 Clusters). CHCs arise from cm-sized, dirty H2 ice balls, called CHIMPs (Contaminated H2 Ice Macro-Particles), formed in cold, dense, Giant Molecular Clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Absorption by the CHIMP of a UV photon releases CHCs. CHCs produce DIBs when they absorb optical photons. When this occurs, the absorbed photon energy disrupts the CHC.

scholarly journals Molecular hydrogen absorption systems in Sloan Digital Sky Survey

2014 ◽  
Vol 440 (1) ◽  
pp. 225-239 ◽  
Author(s):  
S. A. Balashev ◽  
V. V. Klimenko ◽  
A. V. Ivanchik ◽  
D. A. Varshalovich ◽  
P. Petitjean ◽  
...  
Keyword(s):  
Molecular Hydrogen ◽  
Hydrogen Absorption ◽  
Sloan Digital Sky Survey ◽  
Sky Survey

scholarly journals The Nature of Shocks in Molecular Clouds

1989 ◽  
Vol 120 ◽  
pp. 38-43
Author(s):  
Peter W. J. L. Brand
Keyword(s):  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Velocity Profiles ◽  
Hydrogen Emission ◽  
Entire Flow

AbstractEvidence is presented to suggest that the shocked molecular hydrogen emission in the brightest part of the Orion outflow is produced in a J-shock and not a C-shock; that this is true throughout the entire flow; that it may be true in many outflow sources; and that this exacerbates problems with current explanations of the very wide velocity profiles observed in molecular hydrogen emission.

scholarly journals Detection of New Ammonia Sources

1980 ◽  
Vol 87 ◽  
pp. 83-84
Author(s):  
G.H. Macdonald ◽  
A.T. Brown ◽  
L.T. Little ◽  
D.N. Matheson ◽  
M. Felli
Keyword(s):  
Hyperfine Structure ◽  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Column Density ◽  
Rotational Temperature ◽  
Kinetic Temperature ◽  
Excitation Temperature ◽  
Hydrogen Density

Ammonia is a favoured molecule for the study of molecular clouds since several important parameters of the cloud can be deduced from simple observations of the J,K=1,1 and 2,2 inversion doublet transitions and the hyperfine structure in the (1,1) line. With the additional knowledge of the kinetic temperature Tk from observations of CO, for example, it is possible to compute the excitation temperature of the (1,1) line (T11), the rotational temperature between the (1,1) and (2,2) levels (T21), the molecular hydrogen density n(H2) and ammonia column density N(NH3) (see, for example, Martin and Barrett, 1978).

scholarly journals THE IMPLICATIONS OF MOLECULAR HYDROGEN EMISSION

1981 ◽  
Vol 96 ◽  
pp. 167-178 ◽  
Author(s):  
Steven Beckwith
Keyword(s):  
Kinetic Energy ◽  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Seyfert Galaxy ◽  
The Other ◽  
Interstellar Gas ◽  
Vibrationally Excited ◽  
Hydrogen Emission ◽  
Clear Explanation ◽  
Hydrodynamic Calculations

Emission from vibrationally excited molecular hydrogen has been discovered in a variety of objects of widely differing ages and environs including molecular clouds, planetary nebulae, and a Seyfert galaxy. The observations of the H2 spectra indicate this emission arises in hot, nearly thermalized gas. While there is still some disagreement between detailed predictions of hydrodynamic calculations and recent observations, it is generally believed that energy supplied to the interstellar gas in the form of shock waves is responsible for the observed H2 emission.Several of the H2 sources are molecular clouds associated with ongoing star formation, most notably the Orion Molecular Cloud. From the intensity, strength, temperature, and velocity of the molecular hydrogen emission, it is estimated that at least 1048 ergs has been deposited in the cloud over the last thousand years or so in the form of bulk kinetic energy. There is no clear explanation for this process, since the energy is large and the timescale short, and it appears unlikely that we should observe such events unless they occur frequently. Among the other H2 sources in molecular clouds, NGC 7538, DR 21, and W3 are of similar spatial extent and apparent luminosity as the Orion emission.

scholarly journals Supernova Shocks in Molecular Clouds: Velocity Distribution of Molecular Hydrogen

2019 ◽  
Vol 884 (1) ◽  
pp. 81 ◽  
Author(s):  
William T. Reach ◽  
Le Ngoc Tram ◽  
Matthew Richter ◽  
Antoine Gusdorf ◽  
Curtis DeWitt
Keyword(s):  
Velocity Distribution ◽  
Molecular Hydrogen ◽  
Molecular Clouds
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