Flares from Sgr A* and their emission mechanism
by Dodds-Eden, K. and Porquet, D. and Trap, G. and Quataert, E. and Gillessen, S. and Grosso, N. and Genzel, R. and Goldwurm, A. and Yusef-Zadeh, F. and Trippe, S. and Bartko, H. and Eisenhauer, F. and Ott, T. and Fritz, T. K. and Pfuhl, O.
Proceedings of the Galactic Center Workshop 2009, Shanghai
We summarize recent observations and modeling of the brightest Sgr A* flare to be observed simultaneously in (near)-infrared and X-rays to date. Trying to explain the spectral characteristics of this flare through inverse Compton mechanisms implies physical parameters that are unrealistic for Sgr A*. Instead, a “cooling break” synchrotron model provides a more feasible explanation for the X-ray emission. In a magnetic field of about 5-30 Gauss the X-ray emitting electrons cool very quickly on the typical dynamical timescale while the NIR-emitting electrons cool more slowly. This produces a spectral break in the model between NIR and X-ray wavelengths that can explain the differences in the observed spectral indices.
