Soft gamma-ray constraints on a bright flare from the Galactic Center supermassive black hole

Abstract

Sagittarius A* (Sgr A*) is the supermassive black hole residing at the center of the Milky Way. It has been the main target of an extensive multiwavelength campaign we carried out in April 2007. Herein, we report the detection of a bright flare from the vicinity of the horizon, observed simultaneously in X-rays (XMM/EPIC) and near infrared (VLT/NACO) on April 4th for 1-2 h. For the first time, such an event also benefitted from a soft gamma-rays (INTEGRAL/ISGRI) and mid infrared (VLT/VISIR) coverage, which enabled us to derive upper limits at both ends of the flare spectral energy distribution (SED). We discuss the physical implications of the contemporaneous light curves as well as the SED, in terms of synchrotron, synchrotron self-Compton and external Compton emission processes.

30 pages, 5 figures, accepted for publication in ASR

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Cited by in corpus (9)

• A powerful flare from Sgr A* confirms the synchrotron nature of the X-ray emission
• Time Dependent Models of Flares from Sagittarius A*
• Fifteen years of XMM-Newton and Chandra monitoring of Sgr A*: Evidence for a recent increase in the bright flaring rate
• Concurrent X-ray, near-infrared, sub-millimeter, and GeV gamma-ray observations of Sgr A*
• The X-ray flaring properties of Sgr A* during six years of monitoring with Swift
• The Intrinsic Two-Dimensional Size of Sagittarius A*
• INTEGRAL: science highlights and future prospects
• The Galactic LMXB Population and the Galactic Centre Region
• High Energy Emission from the Galactic Center