Disk evolution of the M87’s nucleus observed in 2008

Abstract

Abstract We report the discovery of year-scale X-ray variation in the nuclear region of the M87 by reanalyze the eight Chandra observations from 2007 to 2008. The X-ray spectra are fitted and decomposed into disk and flaring components. This year-scale X-ray variability can be explained quite well by a simple clumpy accretion model. We conclude that the central super-massive black hole of M87 was accreting a cloud of ∼ 0.5 M ⊙ at that time.