Hydrodynamical accretion onto Sagitarius A* from distributed point sources

被引:97
作者
Coker, RF [1 ]
Melia, F [1 ]
机构
[1] UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721
基金
美国国家航空航天局;
关键词
black hole physics; galaxies; nuclei; Galaxy; center; hydrodynamics; ISM; jets and outflows; stars; mass loss;
D O I
10.1086/310925
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Spectral and kinematic studies suggest that the nonthermal radio source Sgr A*, located at the center of the Milky Way, is a supermassive compact object with a mass similar to(2-3) x 100 M.. Winds from nearby stars, located approximate to 0.06 pc to the east of Sgr A*, should, in the absence of any outflow from the putative black hole itself, be accreting onto this object. We report the results of the first three-dimensional Bondi-Hoyle hydrodynamical numerical simulations of this process under the assumption that the Galactic center wind is generated by several different point sources (here assumed to be 10 pseudorandomly placed stars). Our results show that the accretion rate onto the central object can be higher than in the case of a uniform flow since wind-wind shocks dissipate some of the bulk kinetic energy and lead to a higher capture rate for the gas. However, even for this highly nonuniform medium, most of the accreting gas carries with it a relatively low level of specific angular momentum, although large transient fluctuations can occur. Additionally, the post-bow shock focusing of the gas can be substantially different than that for a uniform flow, but it depends strongly on the stellar spatial distribution. We discuss how this affects the morphology of the gas in the inner 0.15 pc of the Galaxy and the consequences for accretion disk models of Sgr A*.
引用
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页码:L149 / L152
页数:4
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