Molecular Hydrogen Line Emission in Seyfert Galactic Nuclei
Abstract
Two-micron spectroscopy of a sample of Seyfert galactic nuclei and starburst galactic nuclei is reported. A large range in the observed S(1) line to Br-gamma line ratio is found, from 0.18 or less in the Seyfert NGC 4151 to about 13 in the starburst nucleus NGC 6240. The range in S(1) line luminosity is nearly three decades. Upper limits on the S(1) line velocity widths in NGC 4151 and the Seyfert NGC 3227 suggest the H2 lines are not formed in the broad-line regions of these galaxies. UV fluorescence is ruled out in the Seyfert NGC 1275 and in the type two Seyfert galaxy NGC 1068, but is a possible mechanism in NGC 4151 and possibly in NGC 3227. Several of the galaxies, most notably NGC 6240 and NGC 1275, have S(1) lines that are overluminous compared to their Br-gamma lines.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1987
- DOI:
- 10.1086/165584
- Bibcode:
- 1987ApJ...320..667F
- Keywords:
-
- Galactic Nuclei;
- Hydrogen Clouds;
- Infrared Spectra;
- Interstellar Gas;
- Seyfert Galaxies;
- Star Formation;
- Vibrational Spectra;
- Emission Spectra;
- Line Spectra;
- Molecular Excitation;
- Spectral Line Width;
- Star Formation Rate;
- Astrophysics;
- GALAXIES: SEYFERT;
- INFRARED: SPECTRA;
- INTERSTELLAR: MOLECULES;
- STARS: FORMATION