The star swallowing luminosity of massive black holes in normal galactic nuclei.
Abstract
The swallowing rate of a black hole of maximum observable mass (approximately 5 x 10 to the 6th solar mass) in an extended stellar system is calculated. The system is assumed to have the form of an isothermal sphere and the properties of the Galactic Nucleus. It is found that if the stellar velocity dispersion is on the order of 200 km/s, the final black hole mass and luminosity are fairly independent of the central density, and in this case the luminosity was found to be 100 times greater. A second calculation was made of the present stellar swallowing rate of a black hole (2 x 10 to the 7th solar masses) in a stellar system having the observed properties of the nucleus M31. A swallowing rate of one star per 10,000 years was found, corresponding to a time-averaged luminosity of 10 to the 42nd erg/s, a factor 100 times greater than the upper limits on the power of a central compact source in either M31 or in the Galactic Nucleus. It is shown therefore, that massive black holes in normal spiral galaxies appear to be turned on in short luminous bursts on the order of 10 to the 44th erg/s. The duty cycle is found to be consistent with Seyfert galaxy statistics.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1984
- Bibcode:
- 1984A&A...131..267S
- Keywords:
-
- Black Holes (Astronomy);
- Galactic Evolution;
- Galactic Nuclei;
- Luminosity;
- Milky Way Galaxy;
- Seyfert Galaxies;
- Accretion Disks;
- Andromeda Galaxy;
- Mass To Light Ratios;
- Quasars;
- Spiral Galaxies;
- Stellar Systems;
- Astrophysics