Condensing Flow model for the Galactic Center

Sergei Nayakshin

1 Max Planck Institut fuer Astrophysik, Garching, Germany


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It is well known that there is as much as   10^4 Solar masses of molecular gas on scales of few pc from the black hole in our Galactic Center. It is likely that a small fraction of this gas is also present at smaller distances where it would form a fossil non-accreting disk. The hot tenuous gas (whose mass is only   0.001 Solar masses according to Chandra observations) will exchange heat, angular momentum, and mass with the molecular gas. Using our recent work on the physics of the interface between the hot and cold phases, we discuss the conditions under which the hot flow will condense on the cool disk. We also present our numerical ZEUS-2D simulations of the dynamics of such a condensing flow. It is found that if the hot gas has a significant angular momentum at the Bondi radius, the emitting spectrum of the condensing flow is in a rough accord with the observations. This therefore opens up a possibility that the black hole is not accreting at all at the present epoch.