Proof of principle X-ray reflection mass measurement of the black hole in H1743-322

TL;DR

This paper demonstrates a novel X-ray reflection spectral method to measure the mass of the black hole in H1743-322, providing a new approach for systems where dynamical measurements are not feasible.

Contribution

It introduces a proof of principle method using X-ray reflection spectra to estimate black hole mass in high-extinction X-ray binaries.

Findings

Estimated black hole mass: 12 ± 2 solar masses

Revised black hole spin: 0.47 ± 0.10

Method proves effective for mass measurement in obscured systems

Abstract

The black hole X-ray binary H1743-322 lies in a region of the Galaxy with high extinction, and therefore it has not been possible to make a dynamical mass measurement. In this paper we make use of a recent model which uses the X-ray reflection spectrum to constrain the ratio of the black hole mass to the source distance. By folding in a reported distance measurement, we are able to estimate the mass of the black hole to be $12\pm2~\text{M}_\odot$ ($1\sigma$ credible interval). We are then able to revise a previous disc continuum fitting estimate of black hole spin $a_*$ (previously relying on a population mass distribution) using our new mass constraint, finding $a_*=0.47\pm0.10$. This work is a proof of principle demonstration of the method, showing it can be used to find the mass of black holes in X-ray binaries.