The `quiescent' black hole in M87
Abstract
It is believed that most giant elliptical galaxies possess nuclear black holes with masses in excess of 10^8 M_solar. Bondi accretion from the interstellar medium might then be expected to produce quasar-like luminosities from the nuclei of even quiescent elliptical galaxies. It is a puzzle that such luminosities are not observed. Motivated by this problem, Fabian & Rees have recently suggested that the final stages of accretion in these objects occurs in an advection-dominated mode with a correspondingly small radiative efficiency. Despite possessing a long-known active nucleus and dynamical evidence for a black hole, the low radiative and kinetic luminosities of the core of M87 provide the best illustration of this problem. We examine an advection-dominated model for the nucleus of M87, and show that accretion at the Bondi rate is compatible with the best-known estimates for the core flux from radio through to X-ray wavelengths. The success of this model prompts us to propose that Fanaroff-Riley (FR)I radio galaxies and quiescent elliptical galaxies accrete in an advection-dominated mode whereas FRII-type radio-loud nuclei possess radiatively efficient thin accretion discs.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1996
- DOI:
- 10.1093/mnras/283.4.L111
- arXiv:
- arXiv:astro-ph/9610097
- Bibcode:
- 1996MNRAS.283L.111R
- Keywords:
-
- ACCRETION;
- ACCRETION DISCS;
- GALAXIES: ACTIVE;
- GALAXIES: INDIVIDUAL: M87;
- Astrophysics
- E-Print:
- 6 pages, 2 postscript figues included. Accepted for publication in MNRAS (pink pages)