THE SPECTRUM OF SGR-A-ASTERISK AND ITS VARIABILITY

We demonstrate that there is only one physical process required to exp lain the spectrum and the variability of the radio source at the dynam ical center of our Galaxy, Sgr A, in the frequency range from almost- equal-to 1 to almost-equal-to 1 000 GHz, namely optically thin synchro tron radiation that is emitted from a population of relativistic elect rons. We attribute the observed variability to variable energy input f rom an accretion disk around Sgr A into the acceleration of the elect rons.