Details

Autor(en) / Beteiligte

• Le Delliou, M.
• Henriksen, R. N.
• MacMillan, J. D.

Titel

Black holes and galactic density cusps

Ist Teil von

• Astronomy and astrophysics (Berlin), 2011-02, Vol.526

Ort / Verlag

EDP Sciences

Erscheinungsjahr

2011

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• Aims. In this paper we continue our study of density cusps that may contain central black holes. Methods. Our previous thus attempts to use distribution functions with a memory of self-similar relaxation apply mainly in restricted regions of the global system. We are forced to consider related distribution functions that are steady but not self-similar. Results. One remarkably simple distribution function that has a filled loss cone describes a bulge that transits from a near black hole domain to an outer “zero flux” regime where ρ ∝ r−7/4. The transition passes from an initial inverse square profile through a region having a 1/r density profile. The structure is likely to be developed at an early stage in the growth of a galaxy. A central black hole is shown to grow exponentially in this background with an e-folding time of a few million years. Conclusions. We derive our results from first principles, using only the angular momentum integral in spherical symmetry. The initial relaxation probably requires bar instabilities and clump-clump interactions.