General relativistic flux modulations in the galactic center black hole candidate sagittarius a*

The proximity of the unique radio source Sgr A* at the Galactic center is allowing us to make unprecedented observations of the spectral formation region near the event horizon of a massive black hole. Near-infrared flux measurements hint at a possible 10.4 minute modulation period in this source, which suggests an emission surface with a Keplerian velocity near the last stable orbit of a 106 M0 Schwarzschild object. In this Letter, we set up the fully general relativistic framework for calculating such modulations, which we suggest might arise from orbiting disk inhomogeneities. The application of our method to the currently available data shows excellent agreement between the calculated light curve and the observed temporal profile, promising exciting future observations of Sgr A* with NICMOS on Hubble Space Telescope.