Markoff, Falcke, Yuan, Biermann 2001: X-ray Flare in Sgr A*

The Nature of the 10 Kilosecond X-ray Flare in Sgr A*

Sera Markoff, Heino Falcke, Feng Yuan, & Peter L. Biermann

Max-Planck-Institut für Radioastronomie, Auf den Hügel 69, D-53121 Bonn, Germany (hfalcke,fyuan,

Astronomy & Astrophysics Letters (2001), Vol. 379, p. L13

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The X-ray mission Chandra has observed a dramatic X-ray flare -- a brightening by a factor of 50 for only three hours - from Sgr A*, the Galactic Center supermassive black hole. Sgr A* has never shown variability of this amplitude in the radio and we therefore argue that a jump of this order in the accretion rate does not seem the likely cause. Based on our model for jet-dominated emission in the quiescent state of Sgr A*, we suggest that the flare is a consequence of extra electron heating near the black hole. This can either lead to bulk heating of thermal electrons to Te~6*1011 K and significantly increased synchrotron-self Compton emission, or result from non-thermal particle acceleration with increased synchrotron radiation and electron Lorentz factors up to gammae≤105. While the former scenario is currently favored by the data, simultaneous VLBI, submm, mid-infrared and X-ray observations should ultimately be able to distinguish between the two cases.

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