An inverse Compton scattering origin of x-ray flares from Sgr A

F. Yusef-Zadeh*, M. Wardle, K. Dodds-Eden, C. O. Heinke, S. Gillessen, R. Genzel, H. Bushouse, N. Grosso, D. Porquet

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    31 Citations (Scopus)


    The X-ray and near-IR emission from SgrA* is dominated by flaring, while a quiescent component dominates the emission at radio and submillimeter (sub-mm) wavelengths. The spectral energy distribution of the quiescent emission from SgrA* peaks at sub-mm wavelengths and is modeled as synchrotron radiation from a thermal population of electrons in the accretion flow, with electron temperatures ranging up to ∼5-20MeV. Here, we investigate the mechanism by which X-ray flare emission is produced through the interaction of the quiescent and flaring components of SgrA*. The X-ray flare emission has been interpreted as inverse Compton, self-synchrotron Compton, or synchrotron emission. We present results of simultaneous X-ray and near-IR observations and show evidence that X-ray peak flare emission lags behind near-IR flare emission with a time delay ranging from a few to tens of minutes. Our inverse Compton scattering modeling places constraints on the electron density and temperature distributions of the accretion flow and on the locations where flares are produced. In the context of this model, the strong X-ray counterparts to near-IR flares arising from the inner disk should show no significant time delay, whereas near-IR flares in the outer disk should show a broadened and delayed X-ray flare.

    Original languageEnglish
    Article number1
    Pages (from-to)1-10
    Number of pages10
    JournalAstronomical Journal
    Issue number1
    Publication statusPublished - Jul 2012


    • black hole physics
    • galaxy: center
    • infrared: general
    • ISM: clouds
    • ISM: general
    • X-rays: general


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