Seyfert galaxies.
Abstract
Recent observational studies of Seyfert galaxies are summarized. The distinctive properties of Seyfert galaxies are described, a working definition of a Seyfert galaxy is provided, and a list is given of 88 Seyferts that satisfy this definition. Surveys of Seyfert galaxies are reviewed, and the morphology of these objects is examined. The deficiency of ellipticals among the Seyfert galaxies is noted, emission-line spectra of various Seyferts are evaluated, and attention is given to the Balmer decrement in Seyfert galaxies, spectral line profiles, Seyfert continua, and luminosities. The relation between the nuclei of Seyfert galaxies and QSOs is discussed together with the use of Seyfert nuclei to demonstrate empirically that QSOs really have cosmological redshifts. Observations of variability in Seyfert galaxies are assessed, and the problem of accounting for the energies of Seyfert nuclei is considered. It is suggested that most of the activity in Seyfert nuclei could arise as a consequence of gravitational accretion onto a black hole or neutron star with a mass of the order of 10 million solar masses.
- Publication:
-
Annual Review of Astronomy and Astrophysics
- Pub Date:
- 1977
- DOI:
- 10.1146/annurev.aa.15.090177.000441
- Bibcode:
- 1977ARA&A..15...69W
- Keywords:
-
- Balmer Series;
- Emission Spectra;
- Line Spectra;
- Quasars;
- Seyfert Galaxies;
- Continuum Mechanics;
- Galactic Nuclei;
- Neutron Stars;
- Radio Sources (Astronomy);
- Red Shift;
- Stellar Mass Accretion;
- Stellar Radiation;
- Tables (Data);
- Astrophysics