EDP Sciences
Free access
Issue
A&A
Volume 375, Number 1, August III 2001
Page(s) L18 - L21
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20010870


A&A 375, L18-L21 (2001)
DOI: 10.1051/0004-6361:20010870

The stellar winds of Galactic Centre and the low accretion rate of Sgr A*

R. F. Coker

Department of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK

(Received 5 June 2001 / Accepted 19 June 2001 )

Abstract
An attempt is made to reconcile the large wind-loss rates of stars in the Galactic Centre (GC) with the predicted low accretion rate for Sgr A*, the putative blackhole at the heart of the Milky Way. It is found that, independent of the details of the accretion, the bound but unaccreted gas has been accumulating in the potential well of Sgr A* for ${\la} 10^3$ yrs and thus is not in equilibrium. Otherwise, the gas flows of the region would be visible in both the IR and X-ray. It appears that the blackhole was more active in the recent past due to the passing of a supernova blast shock but is presently in a short-lived dormant phase. The extended low frequency radio emission from the central parsec should visibily increase over the next few decades, as the shock passes completely in front of the absorbing gas and dust near Sgr A*. The GC may become more active in ${\la} 10^5$ yrs due to either another supernova or sufficient accumulation of stellar winds in the central arcsecond.


Key words: hydrodynamics -- ISM: structure -- stars: winds, outflows -- galaxy: centre -- accretion

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