Insight-HXMT, NuSTAR, and INTEGRAL Data Show Disk Truncation in the Hard State of the Black Hole X-Ray Binary MAXI J1820+070

• Published in: The Astrophysical journal Vol. 928; no. 1; pp. 11 - 18
• Main Authors: Zdziarski, Andrzej A., You, Bei, Szanecki, Michał, Li, Xiao-Bo, Ge, Mingyu
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.03.2022; IOP Publishing
• Subjects: Accretion; Astrophysics; Black holes; Blackbody; Deposition; Gamma ray spectra; Gamma rays; K alpha line; Low-mass x-ray binary stars; Non-thermal radiation sources; Spectra; X ray binaries; X ray stars; X-ray astronomy; X-ray binary stars
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ac54a7

Abstract We study X-ray and soft gamma-ray spectra from the hard state of the accreting black hole binary MAXI J1820+070. We perform an analysis of joint spectra from HXMT, NuSTAR, and INTEGRAL. We find an overall agreement between the spectra from all three satellites. Satisfactory fits to the data require substantial spectral complexity, with our models including two Comptonization regions and their associated disk reflection, a disk blackbody, and a narrow Fe K α line. Our fits confirm the presence of the truncation of the reflecting optically thick disk at least at >10 gravitational radii. However, we find that the HXMT data alone cannot significantly constrain the disk inner radii.