# Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst **Authors:** Yue Zhang, Mingyu Ge, Liming Song, Shuangnan Zhang, Jinlu Qu, Shu, Zhang, Victor Doroshenko, Lian Tao, Long Ji, Can G\"ung\"or, Andrea, Santangelo, Changsheng Shi, Zhi Chang, Gang Chen, Li Chen, Tianxiang Chen,, Yong Chen, Yibao Chen, Wei Cui, Weiwei Cui, Jingkang Deng, Yongwei Dong,, Yuanyuan Du, Minxue Fu, Guanhua Gao, He Gao, Min Gao, Yudong Gu, Ju Guan,, Chengcheng Guo, Dawei Han, Wei Hu, Yue Huang, Jia Huo, Shumei Jia, Luhua, Jiang, Weichun Jiang, Jing Jin, Yongjie Jin, Bing Li, Chengkui Li, Gang Li,, Maoshun Li, Wei Li, Xian Li, Xiaobo Li, Xufang Li, Yanguo Li, Zijian Li,, Zhengwei Li, Xiaohua Liang, Jinyuan Liao, Congzhan Liu, Guoqing Liu, Hongwei, Liu, Shaozhen Liu, Xiaojing Liu, Yuan Liu, Yinong Liu, Bo Lu, Xuefeng Lu, Tao, Luo, Xiang Ma, Bin Meng, Yi Nang, Jianyin Nie, Ge Ou, Na Sai, Liang Sun, Ying, Tan, Wenhui Tao, Youli Tuo, Guofeng Wang, Huanyu Wang, Juan Wang, Wenshuai, Wang, Yusa Wang, Xiangyang Wen, Bobing Wu, Mei Wu, Guangcheng Xiao, Shaolin, Xiong, He Xu, Yupeng Xu, Linli Yan, Jiawei Yang, Sheng Yang, Yanji Yang,, Aimei Zhang, Chunlei Zhang, Chengmo Zhang, Fan Zhang, Hongmei Zhang, Juan, Zhang, Tong Zhang, Wei Zhang, Wanchang Zhang, Wenzhao Zhang, Yi Zhang, Yifei, Zhang, Yongjie Zhang, Zhao Zhang, Ziliang Zhang, Haisheng Zhao, Jianling, Zhao, Xiaofan Zhao, Shijie Zheng, Yue Zhu, Yuxuan Zhu, and Changlin Zou arXiv: 1906.01938 ยท 2019-07-16 ## TL;DR This study uses Insight-HXMT data to analyze the broadband spectrum of the neutron star transient Swift J0243.6+6124 during its 2017-2018 outburst, estimating its magnetic field and luminosity without detecting cyclotron lines. ## Contribution It provides the first broadband spectral analysis of Swift J0243.6+6124 during outburst and estimates its magnetic field and luminosity without observing cyclotron features. ## Key findings - Magnetic field estimated at ~10^13 G - Peak luminosity exceeds 10^39 erg/s - No cyclotron line detected up to 150 keV ## Abstract The recently discovered neutron star transient Swift J0243.6+6124 has been monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT). Based on the obtained data, we investigate the broadband spectrum of the source throughout the outburst. We estimate the broadband flux of the source and search for possible cyclotron line in the broadband spectrum. No evidence of line-like features is, however, found up to $\rm 150~keV$. In the absence of any cyclotron line in its energy spectrum, we estimate the magnetic field of the source based on the observed spin evolution of the neutron star by applying two accretion torque models. In both cases, we get consistent results with $B\rm \sim 10^{13}~G$, $D\rm \sim 6~kpc$ and peak luminosity of $\rm >10^{39}~erg~s^{-1}$ which makes the source the first Galactic ultraluminous X-ray source hosting a neutron star. --- Source: https://tomesphere.com/paper/1906.01938