INFRARED PHOTOMETRY OF THE BLACK HOLE CANDIDATE SAGITTARIUS A

摘要

An infrared source has been imaged within 0.2″ ± 0.3″ of the unique Galactic center radio source Sgr A*. High angular resolution ( < FWHM > ～ 0.55″) was achieved by rapid (～50 Hz) real-time image motion compensation. The source′s near-infrared magnitudes (K = 12.1 ± 0.3, H = 13.7 ± 0.3, and J = 16.6 ± 0.4) are consistent with a hot object reddened by the local extinction (A_υ ～ 27). At the 3 σ level of confidence, a time series of 80 images limits the source variability to less than 50% on timescales from 3 to 30 minutes. The photometry is consistent with the emission from a simple accretion disk model for a ～ 1 x 10~6 solar mass black hole. However, the fluxes are also consistent with a hot luminous (L ～ 10~(3.5-4.6)solar luminosity) central cluster star posi-tionally coincident with Sgr A*.