The spin measurement of MAXI J1348-630 using the Insight-HXMT data

Abstract

We report the results of fitting Insight-HXMT data to the black hole X-ray binary MAXI J1348-430, which was discovered on January 26th, 2019, with the Gas Slit Camera (GSC) on-board MAXI. Several observations at the beginning of the first burst were selected, with a total of 10 spectra. From the residuals of fits using disk plus power law models, X-ray reflection signatures were clearly visible in some of these observations. We use the state-of-the-art $\mathtt {relxill}$ series reflection model to fit six spectra with distinct reflection signatures and a joint fit to these spectra. In particular, we focus on the results for the black hole spin values. Assuming Rin = RISCO, the spin parameter is constrained to be $0.82^{+0.04}_{-0.03}$ with 90% confidence level (statistical only).

An Atypical Low-frequency Quasiperiodic Oscillation Detected in the Hard State of MAXI J1348–630 with Insight-HXMT

“…One type of the discoseismic oscillations in the inner region of the accretion disk: c-modes (or so-called corrugation waves) can naturally produce the oscillations corresponding to the frequency range of LFQPOs in XRBs with very low-spinning BHs (Kato 2001;Silbergleit et al 2001;Tsang & Lai 2009). The BH spin of MAXI J1348−630 is around 0.8 (Kumar et al 2022;Song et al 2023), which is not nearly low enough to produce ∼0.1 Hz oscillation (Silbergleit et al 2001).…”