Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2009-08-20
Astronomy Letters, 2009, v. 35, No. 3, pp. 150-166
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
14 pages, 10 figures
Scientific paper
10.1134/S1063773709030025
Some astrophysical observations of molecular hydrogen point to a broadening of the velocity distribution for molecules at excited rotational levels. This effect is observed in both Galactic and high redshift clouds. Analysis of H_2, HD, and CI absorption lines has revealed the broadening effect in the absorption system of QSO 1232+082 (z_{abs}=2.33771). We analyze line broadening mechanisms by considering in detail the transfer of ultraviolet radiation (in the resonance lines of the Lyman and Werner H_2 molecular bands) for various velocity distributions at excited rotational levels. The mechanism we suggest includes the saturation of the lines that populate excited rotational levels (radiative pumping) and manifests itself most clearly in the case of directional radiation in the medium. Based on the calculated structure of a molecular hydrogen cloud in rotational level populations, we have considered an additional mechanism that takes into account the presence of a photodissociation region. Note that disregarding the broadening effects we investigated can lead to a significant systematic error when the data are processed.
Balashev Sergey A.
Ivanchik Alexandre V.
Varshalovich Dmitry A.
No associations
LandOfFree
Directional Radiation and Photodissociation Regions in Molecular Hydrogen Clouds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Directional Radiation and Photodissociation Regions in Molecular Hydrogen Clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Directional Radiation and Photodissociation Regions in Molecular Hydrogen Clouds will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-526756