Formation of permitted lines in the spectrum of type 1 Seyfert galaxies and quasars. Fe II lines, preliminary discussion.
Abstract
The formation of permitted Fe II lines in type 1 Seyfert galaxies and quasars is investigated in the framework of a classical photoionization model where the Fe II lines are excited at least partly by a fluorescence mechanism. It is assumed that the Fe II emission region is a transition zone without Lyman continuum photons that surrounds the H II region responsible for the broad Balmer lines. The models, methods, and atomic data used in the analysis are described in detail, and results are obtained for a four-level atom. The dominant excitation process is considered, line profiles are discussed, and a model without a central continuum source that excites the Fe II region is tentatively adopted. It is concluded that the Fe II region is probably heated, excited, and ionized by a thermal process.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1979
- Bibcode:
- 1979A&A....72..293C
- Keywords:
-
- Iron;
- Photoionization;
- Quasars;
- Seyfert Galaxies;
- Spectrum Analysis;
- Astronomical Models;
- Balmer Series;
- Electron Transitions;
- H Ii Regions;
- Metal Ions;
- Radiative Recombination;
- Tables (Data);
- Astrophysics;
- Line Formation:Quasars;
- Line Formation:Seyfert Galaxies