Optical emission-line spectra of Seyfert galaxies and radio galaxies.
Abstract
Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from O I and N I through Ne V and Fe VII to Fe X concentrations. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger O III and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission.
- Publication:
-
Physica Scripta
- Pub Date:
- March 1978
- DOI:
- 10.1088/0031-8949/17/3/002
- Bibcode:
- 1978PhyS...17..137O
- Keywords:
-
- Emission Spectra;
- Light Emission;
- Radio Galaxies;
- Seyfert Galaxies;
- Spectral Line Width;
- Balmer Series;
- Line Spectra;
- Radio Emission;
- Radio Spectra;
- Astrophysics;
- Emission Lines:Radio Galaxies;
- Emission Lines:Seyfert Galaxies