Black hole activity in the Milky Way: Echoes and awakenings.

Scientists have detected echoes of light that may be associated with an outburst from the supermassive black hole, Sgr A*, at the center of the Milky Way that took place about 200 years ago. The researchers used the Imaging X-ray Polarimetry Explorer and the Chandra X-ray Observatory to distinguish reflected light from other sources. The resulting data suggests that a low-luminosity event could potentially produce these light echoes given one to two years, and if the inflowing material was close to the maximum amount, then Sgr A* could have output enough energy in just a few hours.