科研之友
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摘要
Recent observations of Sgr A* by Fermi and HESS have detected steady gamma-ray emission in the GeV and TeV bands. We present a new model to explain the GeV gamma-ray emission by inverse Compton scattering by nonthermal electrons supplied by the NIR/X-ray flares of Sgr A*. The escaping electrons from the flare regions accumulate in a region with a size of similar to 10(18) cm and magnetic fields of <= 10(-4) G. Those electrons produce gamma-rays by inverse Compton scattering off soft photons emitted by stars and dust around the central black hole. By fitting the GeV spectrum, we find constraints on the magnetic field and the energy density of optical-UV radiation in the central 1 pc region around the supermassive black hole. While the GeV spectrum is well fitted by our model, the TeV gamma-rays, whose spectral index is different from that of the GeV emission, may be from different sources such as pulsar wind nebulae.
- 出版日期2012-3-20
