Gas-star-interaction in Dense Galactic Nuclei
Abstract
The precursor of a Supermassive Black Hole in the center of a galaxy may be described by a `supermassive star' (SMS) at the center of the galaxy. This is a strongly condensed gas cloud in the center of the central stellar component. The stability and evolution of the SMS depend essentially on the energetic interaction with the stellar component. The structure of the loss-cone (i.e. the part of phase space with stellar orbits crossing the SMS) and the total energy transfer rate to the SMS were recently studied in detail by Amaro-Seoane & Spurzem (2001, astro-ph/0105251, MNRAS in press). They used an estimate of the total cross section of each star when moving through the SMS resulting in a heating rate per dynamical time-scale. This point of view is reasonable for investigating the evolution of the stellar component as a function of radius. For an analysis of the structure and evolution of the SMS itself (i.e. the gaseous component) it is necessary to look on the radial dependance of the energy deposition due to the star-gas interaction. This can be done also semi-analytical in a statistical way by using the dynamical friction concept including a gaseous component (see Just, Kegel & Deiss, 1986, A&A 164, 337). From this the local heating rate of the gas can be estimated and the influence of this (dissipational) process on the stability of the SMS can be investigated. We compute the relevant time-scales as a function of radius for a SMS in the relevant mass range (103 dots 107 Msolar). In the regime of heating time-scales comparable to the evolution time of the SMS we will consider the question of stabilisation against core collapse (resulting in a delay of subsequent formation of a Supermassive Black Hole with the effect of a higher Black Hole mass?).
- Publication:
-
Astronomische Gesellschaft Meeting Abstracts
- Pub Date:
- 2001
- Bibcode:
- 2001AGM....18.P155J