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

TL;DR

This study analyzes NuSTAR data of the ultraluminous X-ray source M82 X-1 using the TCAF model, revealing an intermediate mass black hole with super-Eddington accretion and consistent QPOs, indicating complex accretion dynamics.

Contribution

First application of the TCAF model to M82 X-1 data, deriving black hole mass, accretion properties, and outflow indications from spectral analysis.

Findings

Black hole mass estimated between 156 and 381 solar masses.

Black hole accreting at nearly super-Eddington rate.

Model reproduces observed QPO frequencies.

Abstract

We study the spectral properties and accretion flow behavior of an ultraluminous X-ray source M82\,X-1 using {\it 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$_\odot$. The error weighted average mass of the black hole is $273\pm43$ M$_\odot$, which accreted in nearly super-Eddington rate. The Compton cloud was compact with a size of $\sim13 r_g$ and the shock compression ratio had \textcolor{black}{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.