An accreting black hole model for Sagittarius A

Several observations, notably of broad He I, Br-alpha, and Br-gamma emission lines from the vicinity of IRS 16, indicate the presence of a strong circumnuclear wind near the dynamical center of the Galaxy. Sgr A, a hypothesized supermassive object situated about 0.06 pc to the west of IRS 16, should be accreting from this wind if it is not itself a source of gaseous outflow, for which there is currently no observational evidence. Here, the spectrum and flux of radiation resulting from this process are calculated, and it is shown that they are consistent with the data over at least 12 decades of frequency. Together with the kinematic studies of the stellar and gas distributions in this region, the model argues strongly in favor of Sgr A being a black hole with mass over a million solar masses.