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Published April 2022 | Published + Accepted Version
Journal Article Open

Detailed analysis on the reflection component for the black hole candidate MAXI J1348-630


The black hole candidate MAXI J1348-630 was discovered in 2019 January 26, with the Gas Slit Camera (GSC) on-board MAXI. We report a detailed spectral analysis of this source by using the archived data of NuSTAR. A total of nine observations covered the complete outburst evolution of MAXI J1348-630 from the hard state to the soft state and finally back to the hard state. Additionally, the intermediate state is found in the transition from the hard state to the soft state. We use the state-of-the-art reflection model relxill family to fit all the nine spectra, and the spectra from two focal plane module detectors of NuSTAR are jointly fitted for each observation. In particular, we concentrate on the results of the black hole spin parameter and the inclination of the accretion disc. Based on the analysis of the inner radius of the accretion disc, we obtain the spin parameter a∗ = 0.78^(+0.04)_(−0.04)⁠, and the inclination angle of the inner disc i = 29.2^(+0.3)_(−0.5)°. Furthermore, we also find that when the black hole is in the hard state, the accretion disc would show a significant truncation. The high iron abundance and ionization of the accretion disc obtained in the fitting results can be possibly explained by the high density of the accretion disc.

Additional Information

© 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2022 January 12. Received 2022 January 11; in original form 2021 July 14. Published: 04 February 2022. This work has made use of data obtained from the NuSTAR satellite, a Small Explorer mission led by the California Institute of Technology (Caltech) and managed by NASA's Jet Propulsion Laboratory in Pasadena. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software, NuSTARDAS, jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). LG is supported by the National Program on Key Research and Development Project (Grant No. 2016YFA0400804) and by the National Natural Science Foundation of China (Grant No. U1838114), and by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB23040100). JW acknowledges the support of the National Natural Science Foundation of China (NSFC grant No. U1938105) and the President Fund of Xiamen University (No. 20720190051). Data Availability: The data underlying this article are observed by NuSTAR which is accessed from https://heasarc.gsfc.nasa.gov/xamin

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August 22, 2023
October 24, 2023