A&A 379, L13-L16 (2001)
The Nature of the 10 kilosecond X-ray flare in Sgr A*S. Markoff, H. Falcke, F. Yuan and P. L. Biermann
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
(Received 6 September 2001 / Accepted 26 September 2001)
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 direct heating of thermal electrons to 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 . 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.
Key words: galaxy: center -- galaxies: jets -- X-rays: galaxies -- radiation mechanisms: non-thermal -- accretion, accretion disks -- black hole physics
Offprint request: S. Markoff, firstname.lastname@example.org
© ESO 2001