Hydroxyl absorption in NGC 520, NGC 2623, 6240.
Abstract
Extragalactic absorption of hydroxyl is reported for the galaxies NGC 520, NGC 2623, and NGC 6240. H I absorption has also been detected in these galaxies. The properties of the H I and OH absorption features are compared for these galaxies and for other galaxies with absorption in both OH and H I. the hyperfine ratio for the 1667 and 1665 MHz hydroxyl transitions for most extragalactic absorption lines falls within LTE range. The characteristics of extragalactic OH absorption lines are consistent with the existence of dense molecular disks in the inner parts of the galaxies. An asymmetry in a number of extragalactic OH absorption lines suggests a peculiar velocity structure for the absorbing molecular disk.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1985
- DOI:
- 10.1086/163245
- Bibcode:
- 1985ApJ...293..394B
- Keywords:
-
- Absorption Spectra;
- Galactic Nuclei;
- Hydroxyl Radicals;
- Interstellar Gas;
- Radio Astronomy;
- Hydrogen Clouds;
- Line Spectra;
- Optical Thickness;
- Astrophysics