The recent detection of variable infrared emission from Sagittarius A*,combined with its previously observed flare activity in X-rays, providescompelling evidence that at least a portion of this object's emission isproduced by nonthermal electrons. We show here that acceleration of electronsby plasma wave turbulence in hot gases near the black hole's event horizon canaccount both for Sagittarius A*'s mm and shorter wavelengths emission in thequiescent state, and for the infrared and X-ray flares, induced either via anenhancement of the mass accretion rate onto the black hole or by areorganization of the magnetic field coupled to the accretion gas. Theacceleration model proposed here produces distinct flare spectra that may becompared with future coordinated multi-wavelength observations. We furthersuggest that the diffusion of high energy electrons away from the accelerationsite toward larger radii might be able to account for the observedcharacteristics of Sagittarius A*'s emission at cm and longer wavelengths.
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