Radiatively Inefficient Accretion Flow Models of Sgr A*
Abstract
I review radiatively inefficient accretion flow models for the 2.6 million solar mass black hole (BH) in the Galactic Center. I argue for a 'concordance model' of Sgr A*: both theory and observations suggest that hot ambient gas around the BH is accreted at a rate of order 10^{-8} solar masses/year, much less than the canonical Bondi rate. I interpret Chandra observations of Sgr A* in the context of such a model: (1) the extended 'quiescent' X-ray emission is due to thermal bremsstrahlung from gas in the vicinity of the Bondi accretion radius, and (2) the ~ ksec long X-ray flares are due to synchrotron or Inverse-Compton emission by non-thermal electrons accelerated in the inner 10 Schwarzschild radii of the accretion flow.
Keywords
Cite
@article{arxiv.astro-ph/0304099,
title = {Radiatively Inefficient Accretion Flow Models of Sgr A*},
author = {Eliot Quataert},
journal= {arXiv preprint arXiv:astro-ph/0304099},
year = {2009}
}
Comments
9 pages; to appear in Astron. Nachr., Vol. 324, No. S1 (2003), Special Supplement "The central 300 parsecs of the Milky Way", Eds. A. Cotera, H. Falcke, T. R. Geballe, S. Markoff