Spectral analysis of new black hole candidate AT2019wey observed by NuSTAR

作     者：Ye Feng XueShan Zhao LiJun Gou YuFeng Li James FSteiner Javier AGarc´ıa Yuan Wang Nan Jia ZhenXuan Liao HuiXian Li Ye Feng;XueShan Zhao;LiJun Gou;YuFeng Li;James F.Steiner;Javier A.García;Yuan Wang;Nan Jia;ZhenXuan Liao;HuiXian Li

作者机构：Key Laboratory for Computational AstrophysicsNational Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China School of Astronomy and Space SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Harvard-Smithsonian Center for AstrophysicsCambridge MA 02138USA Cahill Centre for Astronomy and AstrophysicsCalifornia Institute of TechnologyPasadena CA 91125USA Dr.Karl Remeis-Observatory and Erlangen Centre for Astroparticle PhysicsBamberg 96052Germany School of ScienceJimei UniversityXiamen 361021China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2022年第65卷第1期

页      面：92-102页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400804) the National Natural Science Foundation of China(Grant No.U1838114) the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040100) 

主　　题：NuSTAR black hole physics X-rays binaries-stars individual AT2019wey 

摘      要：AT2019 wey is a new galactic X-ray binary that was first discovered as an optical transient by the Asteroid Terrestrial-impact Last Alert System(ATLAS)on December 7,***2019 wey consists of a black hole candidate as well as a low-mass companion star(M_(star)≤1.0 M_(■))and is likely to have a short orbital period(P_(orb)≤16h).Although AT2019 wey began activation in the X-ray band on March 8,2020,it did not enter the soft state during almost the entire *** this study,we present a detailed spectral analysis of AT2019 wey in the low/hard state during its X-ray outburst on the basis of Nuclear Spectroscopic Telescope Array(Nu S T AR)*** obtain tight constraints on several of its important physical parameters by applying the state of the art relxill relativistic reflection model *** particular,we determine that the measured inner radius of the accretion disk is most likely to have extended to the innermost stable circular orbit(ISCO)radius,i.e.,R_(in)=1.38^(+0.23)_(-0.16)R_(ISCO).Hence,assuming R_(in)=R_(ISCO),we find the spin of AT2019 wey to be a*~0.97,which is close to the extreme and an inner disk inclination angle of i~22°.Additionally,according to our adopted models,AT2019 wey tends to have a relatively high iron abundance of AFe~5A_(Fe,■)and a high disk ionization state of logξ~3.4.