What is the accretion rate in Sagittarius A *?

Eliot Quataert, Ramesh Narayan, Mark J. Reid

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


The radio source Sagittarius A* at the center of our Galaxy is believed to be a 2.6 x 106 M⊙ black hole that accretes gas from the winds of nearby stars. We show that limits on the X-ray and infrared emission from the Galactic center provide an upper limit of ∼8 x 10-5 M⊙ yr- on the mass accretion rate in Sgr A*. The advection-dominated accretion flow (ADAF) model favors a rate of ≲10-5 M⊙ yr-1. In comparison, the Bondi accretion rate onto Sgr A*, estimated using the observed spatial distribution of mass-losing stars and assuming noninteracting stellar winds, is ∼3 x 10-5 M⊙ yr-1. Thus, there is rough agreement between the Bondi, the ADAF, and the X-ray-inferred accretion rates for Sgr A*. We discuss uncertainties in these estimates, emphasizing the importance of upcoming observations by the Chandra X-ray Observatory for tightening the X-ray-derived limits.

Original languageEnglish (US)
Pages (from-to)L101-L104
JournalAstrophysical Journal
Issue number2 PART 2
StatePublished - Jun 1 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Accretion, accretion disks
  • Black hole physics
  • Galaxy: center


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