1. Confirming the spin parameter of the black hole in Cygnus X-1 using the Insight-HXMT
- Author
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Yongjie Zhang, Xian Li, Sheng Yang, Zi-Liang Zhang, Yan-Ting Dong, Lian Tao, X. Y. Song, Yupeng Xu, YongJie Jin, Ji-Ren Liu, Mei Wu, T. Luo, Jing Jin, Wan-Chang Zhang, GuoQing Liu, Chen Wang, Wei Cui, S. Xiao, XiangYang Wen, Yu-Dong Gu, Jianyin Nie, Jing-Kang Deng, Xiao-Fan Zhao, J. W. Yang, Yanji Yang, Xiaobo Li, Jia Huo, Yuan You, Gang Li, Youli Tuo, Mao-Shun Li, Qi-Bin Yi, Xufang Li, B. S. Liu, Zheng-Wei Li, Jin-Lu Qu, Yanguo Li, Xue-Ying Zheng, Yu-Peng Chen, Wei Zhang, Cheng-Cheng Guo, Yi Zhang, Li-Ming Song, Juan Zhang, N. Sai, C. Cai, Shaolin Xiong, Xue-Feng Lu, ShiJie Zheng, Jian-Feng Zhou, Q. Luo, Y. P. Chen, L. D. Kong, Wei-Wei Cui, Yongwei Dong, Yuan-Yuan Du, Bing Li, Da-Wei Han, Bin Meng, HongMei Zhang, Li-Jun Gou, Ying Tan, Zhi Zhang, C. L. Zhang, Juan Wang, D. K. Zhou, Shu Zhang, Min-Xue Fu, Jin-Yuan Liao, X. L. Cao, H. T. Liu, LuHua Jiang, Hai-Sheng Zhao, Yu-Sa Wang, X. H. Liang, Ye Feng, Yue Zhang, Guang-Cheng Xiao, Bo Lu, Qingcui Bu, Fangjun Lu, He Gao, Li Chen, Ju Guan, Yong Chen, B. B. Wu, Tong Zhang, Guan-Hua Gao, Shu-Mei Jia, W. S. Wang, Ge Ou, W. C. Jiang, Liang Sun, Tian-Xiang Chen, Qian-Qing Yin, Wei Li, Y. Nang, G. F. Wang, Xiang Ma, Yue-Zhu, Zhao Zhang, W. Z. Zhang, Nan Jia, Fan Zhang, Yu-Xuan Zhu, Yifei Zhang, Shuang-Nan Zhang, Aimei Zhang, Ming-Yu Ge, Xiao-Jing Liu, Yu-Feng Li, Yue Huang, R. C. Shang, Zhi Chang, Zhen-Xuan Liao, H. W. Liu, Gang Chen, Cheng-Kui Li, Yi-Rong Yang, Y. N. Liu, Bobing Wu, Ti-Pei Li, M. Gao, Xue-Shan Zhao, R. L. Zhuang, and C. X. Liu
- Subjects
Physics ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Spectral line ,Orbital inclination ,law.invention ,Telescope ,Rotating black hole ,Space and Planetary Science ,Fitting methods ,law ,0103 physical sciences ,System parameters ,010303 astronomy & astrophysics ,Spin-½ ,Dimensionless quantity - Abstract
Recently, the system parameters of Cygnus X-1, i.e., the black hole mass M, the orbital inclination i and the source distance D, have been updated. As the input constraints of the continuum-fitting method, it is necessary to refine the spin with these new parameters. The Hard X-ray Modulation Telescope (HXMT, also named Insight) was successfully launched on June 15th, 2017 in China. In this work, we analyzed spectra obtained by the Insight-HXMT during 2017-2018 and re-estimated the spin via the continuum-fitting method. We first re-estimated the spin using old parameters and found the dimensionless spin parameter to be a ⁎ > 0.934 (3σ), which is consistent with previous measurements both from the continuum-fitting and iron-line fitting methods ( Gou et al. 2011 , Gou et al. 2014 ; Fabian et al. 2012 , Walton et al. 2016 , Tomsick et al. 2018 ). Then, when the new parameters were applied, we obtained an increased spin: a ⁎ > 0.967 (3σ), which is also consistent with the recent measurement (Zhao et al. 2020, submitted to ApJ) and also confirms an extreme Kerr black hole lying in this system.
- Published
- 2020
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