Sgr A*, the radio source associated with the central supermassive black hole,
is quite underluminous as compared to black holes at the centers of other galaxies.
However, with the increased sensitivity provided by adaptive optics, the infrared emission
from material accreting onto Sgr A* has been detected. The emission is variable, and the
luminosity of Sgr A* can increase by a factor of a few over the stellar background during a single night.
The recent discovery of the gas cloud plunging toward the supermassive black hole has opened a new window opportunity to explore accretion flow physics in an extreme gravitational potential. If this object (G2) is indeed a gas cloud, it would be ripped apart by the tidal forces of the SMBH during closest approach and then accreted. Recent measurement done by our groups have shown that this object is more likely harbor a star inside. Overall, the infall of G2, whatever its exact nature, provides a rare and exciting opportunity to follow a predicted accretion event, offering an unprecedented window into black hole accretion physics.