Study of accretion flows around an ultraluminous X-ray source M82 X-1 using NuSTAR data

Abstract

We study the spectral properties and accretion flow behavior of an ultraluminous X-ray source M82 X-1 using NuSTAR observations. We use the physical two-component advective flow (TCAF) model to fit the data and to derive the accretion flow properties of the source. From the model fitted parameters, we found that M82 X-1 is harboring an intermediate mass black hole at its centre, where the mass varies from 156.04+13.51 −15.30 to 380.96+28.38 −29.76 M. The error weighed average mass of the black hole is 273 ± 43 M, which accreted in nearly super-Eddington rate. The Compton cloud was compact with a size of ∼13rg and the shock compression ratio had nearly intermediate values except for the epoch four. These indicate a possible significant mass outflow from the inner region of the disk. The quasi periodic oscillation (QPO) frequencies estimated from the model fitted parameters can reproduce the observed QPOs. The robustness of the model parameters is verified by drawing the confidence contours among them.