Galaxy mergers and active nuclei. I. The luminosity function

Journal Article · Mon Jul 15 04:00:00 EDT 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/163314· OSTI ID:5266921

Roos, N

Galaxy mergers may boost the tidal disruption rate of stars near a massive central black hole in the nucleus of a galaxy, producing active galactic nuclei (AGNs) with nonthermal luminosities up to 10/sup 47/ ergs s/sup -1/. We derive a bolometric luminosity function for AGNs based on this process. Our main assumptions are: (1) galaxies contain massive central black holes, and (2) the density structure of galactic nuclei is similar to that of the Milky Way. The merging rate is estimated from the two-point correlation function of galaxies. Our bolometric luminosity function can be compared with observed radio, optical, and X-ray luminosity functions by assuming that the energy emitted at these wavebands is proportional to bolometric luminosity. This assumption is based on the similarity between observed luminosity functions at high luminosities. The observed and theoretical functions have the same characteristics: at high luminosities they behave as a power law with index of about -1.4. The function flattens below L/sup direct-product/roughly-equal10/sup 44/ ergs s/sup -1/. As an example we show that the model is capable of reproducing in detail the observed (bivariate) radio luminosity function. The luminosity coordinate of the break in the (bivariate) radio luminosity function at L/sup direct-product/ yields an estimate of the central black-hole mass as a function of (stellar) galactic luminosity. The space-density coordinate of the break indicates that the mean mass ratio of the interacting galaxies is larger than 20.

• Research Organization: Sterrewacht, Leiden, The Netherlands
• OSTI ID: 5266921
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 294:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BLACK HOLES
GALAXIES
GALAXY CLUSTERS
GALAXY NUCLEI
LUMINOSITY
MASS
MATHEMATICAL MODELS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES