2011ApJ...728L..10L -
Astrophys. J., 728, L10 (2011/February-2)
The murmur of the hidden monster: chandra's decadal view of the supermassive black hole in M31.
LI Z., GARCIA M.R., FORMAN W.R., JONES C., KRAFT R.P., LAL D.V., MURRAY S.S. and WANG Q.D.
Abstract (from CDS):
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, or only ∼10–10 of its Eddington luminosity. We report the discovery of an outburst that occurred on 2006 January 6 during which M31* radiated at ∼4.3x1037 erg/s. After the outburst, M31* entered a more active state that apparently lasts to the present, which is characterized by frequent flux variability around an average luminosity of ∼4.8x1036 erg/s. These flux variations are similar to the X-ray flares found in the SMBH of our Galaxy (Sgr A*), making M31* the second SMBH known to exhibit recurrent flares. Future coordinated X-ray/radio observations will provide useful constraints on the physical origin of the flaring emission and help rule out a possible stellar origin of the X-ray source.
Abstract Copyright:
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Journal keyword(s):
galaxies: individual: M31 - galaxies: nuclei - X-rays: galaxies
Nomenclature:
Fig. 1: [LGF2011] S1 N=1.
CDS comments:
SSS = [KGP2002] r1-9, N1 = [KGP2002] r1-10
Simbad objects:
9
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