Hydrodynamical accretion onto sagittarius A* from distributed point sources

Robert F. Coker, Fulvio Melia

Research output: Contribution to journalArticle

87 Citations (Scopus)

Abstract

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 ∼(2-3) × 106 M. Winds from nearby stars, located ≈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*.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume488
Issue number2 PART II
StatePublished - 1997

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point sources
point source
accretion
uniform flow
gases
gas
shock
stars
bows
accretion disks
angular momentum
kinetic energy
spatial distribution
outflow
kinematics
radio
galaxies
simulation
rate

Keywords

  • Black hole physics
  • Galaxies: nuclei
  • Galaxy: center
  • Hydrodynamics
  • ISM: jets and outflows
  • Stars: mass loss

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Hydrodynamical accretion onto sagittarius A* from distributed point sources. / Coker, Robert F.; Melia, Fulvio.

In: Astrophysical Journal, Vol. 488, No. 2 PART II, 1997.

Research output: Contribution to journalArticle

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AU - Melia, Fulvio

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KW - Hydrodynamics

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KW - Stars: mass loss

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