Near-infrared and X-ray quasi-periodic oscillations in numerical models of Sgra*

Joshua C. Dolence, Charles F. Gammie, Hotaka Shiokawa, Scott C. Noble

Research output: Contribution to journalArticlepeer-review


We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source SgrA*. The QPOs result from nonaxisymmetric m = 1 structure in the accretion flow excited by MHD turbulence. Near-infrared (NIR) and X-ray power spectra show significant peaks at frequencies comparable to the orbital frequency at the innermost stable circular orbit (ISCO) fo . The excess power is associated with inward propagating magnetic filaments inside the ISCO. The amplitudes of the QPOs are sensitive to the electron distribution function. We argue that transient QPOs appear at a range of frequencies in the neighborhood of fo and that the power spectra, averaged over long times, likely show a broad bump near fo rather than distinct, narrow QPO features.

Original languageEnglish (US)
Article numberL10
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Feb 10 2012


  • Galaxy: center
  • accretion, accretion disks
  • black hole physics
  • magnetohydrodynamics (MHD)
  • methods: numerical
  • radiative transfer

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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