Measuring the Spin of Black Hole Transient 4U 1543-47 Using Insight-HXMT

TL;DR

This study estimates the black hole spin in 4U 1543-47 during its 2021 outburst using Insight-HXMT X-ray data, employing reflection fitting methods and discussing model limitations.

Contribution

First estimation of black hole spin in 4U 1543-47 using Insight-HXMT data with spectral reflection fitting, highlighting model limitations and potential overestimation.

Findings

Black hole spin estimated at ~0.9 with statistical confidence.

Inclination angle of the accretion disk determined to be ~29 degrees.

Discussion on the impact of high luminosity and model suitability.

Abstract

We provided a comprehensive study of the properties of the black hole in the low-mass X-ray binary system 4U 1543-47, specifically focusing on the 2021 outburst (MJD 59380-59470). Using observations from the \textit{Insight}-HXMT mission, we employed X-ray reflection fitting method and analyzed spectral data to estimate key black hole parameters. Through our investigation redbased on 6 out of the 52 available observations, we estimated the spin parameter of the black hole to be $0.902_{-0.053}^{+0.054}$ and the inclination angle of the accretion disk to be $28.91_{-1.24}^{+1.82}$ degrees (90\% confidence limits, statistical only), then we discussed the influence of high luminosity. Based on the \texttt{relxill} series models are not suitable for thick disk scenario, and in comparison with findings from other studies, we propose that our estimation of the spin value may be exaggerated.