The year-scale X-ray variations in the core of M87

Abstract The analysis of light variation M87 can help us understand the disc evolution. In past decade, has experienced several short-term variabilities related to flares. We also find there are year-scale X-ray variations in core M87. Their variability properties similar clumpy-ADAF. By re-analyzing 56 Chandra observations from 2007 2019, we distinguish ‘non-flaring state’ ‘flaring variability. After removing flaring state data, identify 4 gas clumps nucleus and all them be well fitted by clumpy-ADAF model. average mass accretion rate is ∼ 0.16M⊙yr−1. analyze photon index(Γ) — flux(2-10keV) correlation between non-flaring state. For states, flux inversely proportional index. no obvious two parameters. addition, that flare always occurs at a high rate, after luminosity reaches peak, it will accompanied sudden decrease luminosity. Our results explained as energy released magnetic reconnection destroys structure disc, thus decreases rapidly returns normal levels thereafter.