EDP Sciences
Free Access
Volume 379, Number 1, November III 2001
Page(s) L13 - L16
Section Letters
DOI https://doi.org/10.1051/0004-6361:20011346
Published online 15 November 2001

A&A 379, L13-L16 (2001)
DOI: 10.1051/0004-6361:20011346

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 $T_{\rm
e}\sim6\times 10^{11}$ 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 $\gamma_{\rm e}\ga10^{5}$. 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, smarkoff@mpifr-bonn.mpg.de

SIMBAD Objects

© ESO 2001

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.