Spherical accretion in nearby weakly active galaxies

Free access article

Issue		A&A Volume 450, Number 1, April IV 2006


Page(s)		93 - 103
Section		Extragalactic astronomy
DOI		http://dx.doi.org/10.1051/0004-6361:20054165

A&A 450, 93-103 (2006)
DOI: 10.1051/0004-6361:20054165

Spherical accretion in nearby weakly active galaxies

M. Moscibrodzka

N. Copernicus Astronomical Center, Bartycka 18, 00-716, Warsaw, Poland
e-mail: mmosc@camk.edu.pl

(Received 6 September 2005 / Accepted 15 December 2005 )

Abstract
We consider the sample of weakly active galaxies situated in the "Local Universe" with inferred accretion efficiencies from 10^-2 to 10^-7. We apply a model of spherically symmetrical Bondi accretion for given parameters ( $M_{{\rm BH}}$ , $T_{\infty}$ , $\rho_{\infty}$ ,) taken from observation. We calculate spectra emitted by the gas accreting onto its central objects using a Monte Carlo method including synchrotron and bremsstrahlung photons as seed photons. We then compare our results with observed nuclear X-ray luminosities $L_{{\rm X,\;nuc}}$ (0.3-10 keV) for the sample. A model is also tested for different external medium parameters ( $\rho_{\infty}$ and $T_{\infty}$ ) and different free parameters of the model. Our model is able to explain observed nuclear luminosities $L_{\rm X}$ under an assumption that half of the compression energy is transferred directly to the electrons.

Key words: galaxies: nuclei -- galaxies: active -- galaxies: cooling flows

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