Physical Sciences and Mathematics Commons^™

The Murmur Of The Hidden Monster: Chandra's Decadal View Of The Supermassive Black Hole In M31, Z Li, Mr Garcia, Wr Forman, C Jones, Rp Kraft, Dv Lal, Ss Murray, Qd Wang

Astronomy Department Faculty Publication Series

The Andromeda galaxy (M31) hosts a central supermassive black hole (SMBH), known as M31*, which is remarkable for its mass (~10⁸ M ) and extreme radiative quiescence. Over the past decade, the Chandra X-Ray Observatory has pointed to the center of M31 ~100 times and accumulated a total exposure of ~900 ks. Based on these observations, we present an X-ray study of a highly variable source that we associate with M31* based on positional coincidence. We find that M31* remained in a quiescent state from late 1999 to 2005, exhibiting an average 0.5-8 keV luminosity 10³⁶ erg s …