A moderate spin for the black hole in X-ray binary MAXI J1348−630 revealed by Insight-HXMT

Abstract

MAXI J1348-630 is a low-mass X-ray black hole binary located in the Galaxy and undergone the X-ray outburst in 2019. We analyzed the observation data in very soft state during the outburst between MJD 58588 and MJD 58596 based on the Insight-HXMT observations from 2 – 20 keV via the continuum fitting method to measure the spin of the stellar-mass black hole in MAXI J1348-630. The inner disk temperature and the apparent inner disk radius were found to be $0.47\pm 0.01 \rm keV$ and 5.33 ± 0.10 Rg from the observation data modeled by the multicolor disc blackbody model. Assuming the distance of the source $D\sim 3.4 \rm kpc$, the mass of the black hole M ∼ 11 M⊙, and the inclination of the system i ∼ 29.2○, the spin is determined to be a⋆ = 0.41 ± 0.03 for fixing hardening factor at 1.6 and $n_{H}=8.6\times 10^{21} \rm cm^{-2}$. Besides, considering the uncertainty of the parameters D, M, i of this system, with the Monte Carlo analysis, we still confirm the moderate spin of the black hole as $a_{\star }=0.42^{+0.13}_{-0.50}$. Some spectral parameters (e.g., column density and hardening factor) which could affect the measurements of the BH spin are also briefly discussed.

The Shock Cone Instabilities and Quasi-Periodic Oscillations around the Hartle–Thorne Black Hole

“…These studies involve analyzing how matter behaves in the extreme conditions near the black hole, including how it orbits, the speeds it reaches, and the ways in which it emits radiation (like X-rays) as it falls into the black hole. Understanding the generation and characteristics of these QPOs not only helps in probing the environment near black holes [25] but also provides valuable information about the properties of the black holes themselves, such as their mass, spin, and the nature of their gravitational pull [30][31][32][33][34].…”