Volume 387, Number 2, May IV 2002
|Page(s)||422 - 428|
|Section||Cosmology (including clusters of galaxies)|
|Published online||13 May 2002|
Where have all the black holes gone?
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2 Institut für Theoretische Astrophysik, Tiergartenstraße 15, 69121 Heidelberg, Germany
Corresponding author: T. Beckert, firstname.lastname@example.org
Accepted: 18 March 2002
We have calculated stationary models for accretion disks around super-massive black holes in galactic nuclei. Our models show that below a critical mass flow rate of advection will dominate the energy budget while above that rate all the viscously liberated energy is radiated. The radiation efficiency declines steeply below that critical rate. This leads to a clear dichotomy between AGN and normal galaxies which is not so much given by differences in the mass flow rate as by the radiation efficiency. At very low mass accretion rates below synchrotron emission and Bremsstrahlung dominate the SED, while above the inverse Compton radiation from synchrotron seed photons produce flat to inverted SEDs from the radio to X-rays. Finally we discuss the implications of these findings for AGN duty cycles and the long-term AGN evolution.
Key words: accretion, accretion disks / black hole physics / radiation mechanisms: non-thermal / galaxies: active / galaxies: nuclei
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.