Estimating the Black Hole Spin for the X-Ray Binary MAXI J1727-203 Based on Insight-HXMT

We constrain the spin of the black hole candidate MAXI J1727-203 using Insight-HXMT data. Due to limited Insight-HXMT observations covering only part of the outburst, NICER data were used to analyze the full outburst’s state transitions; we identified two of three HXMT observations in the high soft...

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Bibliographic Details
Main Authors: Haifan Zhu, Wei Wang
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adae8b
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Summary:We constrain the spin of the black hole candidate MAXI J1727-203 using Insight-HXMT data. Due to limited Insight-HXMT observations covering only part of the outburst, NICER data were used to analyze the full outburst’s state transitions; we identified two of three HXMT observations in the high soft state and applied the continuum-fitting method to measure the spin. Based on previous estimates and continuum spectral fittings, we explored the parameter space and found that the best-fitting values were ( D , i , M ) ≈ (6 kpc, 30°, 12 M _⊙ ). We also tested the variation of these parameters using Monte Carlo simulations, sampling over 3000 sets within the parameter ranges 5.9 kpc <  D  < 7 kpc, 24° <  i  < 35°, and 10 M _⊙ < M < 14 M _⊙ , yielding a spin measurement of $a=0.3{4}_{-0.19}^{+0.15}$ (1 σ ). In addition, we analyzed NuSTAR data in the low hard state and found a good fit with the tbabs∗(diskbb+powerlaw) model, with no significant iron line features observed in the residuals; therefore, the previous reflection model results suggesting an extremely high spin overestimates the black hole spin.
ISSN:1538-4357