THE GALACTIC-CENTER RADIO JET

Recent observations of the radio and NIR source Sgr A reinforce the i nterpretation of the Galactic Center as a scaled down version of an AG N. The discovery of an elongated structure at 43 GHz and increasing ev idence for the presence of an accretion disk surrounding a Black Hole lead us to assume that both, an accretion disk and a jet, are present in the Galactic Center and are physically linked. We model the radio e mission of Sgr A successfully with a Blandford & Konigl type jet and analyze the energetics of the coupled jet-disk system in Sgr A where jet and disk are parametrized in terms of the accretion power. With th is method we are able to confirm independently the lower limit of the Sgr A accretion rate M >> 10(-8.5) M. found previously. Moreover, usi ng the limits imposed by observational data, we show that within such a jet-disk model, the total jet power Q(jet) is of comparable order as the radiated disk luminosity L(disk). A jet model together with the a ssumption of an 10(6) M. Black Hole also qualitatively explains the su bmm excess and the lack of non-thermal IR radiation. The small size of the visible part of the jet (< 1 mas) is due to the low accretion rat e of Sgr A.