Timing analysis of the black hole candidate EXO 1846–031 with Insight-HXMT monitoring

He-Xin Liu,Bai-Yang Wu,Shuo Xiao,Yi-Jung Yang,Xian Li,Lingjun Wang ,Fangjun Lu ,Fan Zhang,Yue Zhang,Wei Cui,Zhi Chang,Bing Li,Weng-Shuai Wang,J L Qu ,Ying Tan,R C Shang ,Liming Song ,Luhua Jiang ,G Ou ,Yuxuan Zhu ,Zhao Zhang,T Luo ,Juan Wang,D K Zhou ,S M Jia ,Bo Lü ,Jing Jin,Yongwei Dong ,Aimei Zhang ,S Yang ,N Sai ,Danxiang Han ,H S Zhao ,X F Lu ,Weichun Jiang ,Haiqiang Jia ,Ti-Pei Li,He Gao,Bin Meng,G H Gao ,Guofeng Wang ,Guoqing Liu ,Chengmo Zhang ,J K Deng ,Tianxiang Chen ,Ziliang Zhang ,Yu-Peng Chen,Yong Chen,Yang-Guo Li,Wei Zhang,X H Liang ,S L Xiong ,Lian Tao,L D Kong ,Y D Gu ,C Cai ,You-Li Tuo,Yifei Zhang ,Xiang Ma,Min Gao,R L Zhuang ,Yusa Wang ,G C Xiao ,X Y Song ,Q Luo ,He Xu,Yinong Liu ,Q C Bu ,Y Y Du ,Yupeng Xu ,Y Nang ,Cong‐Zhan Liu ,Cheng-Kui Li,Xiang-Yang Wen,Xiaobo Li ,J Y Liao ,Y You ,Weiwei Cui ,Chen Wang,Tong Zhang,Y Huang ,Shuang‐Nan Zhang ,Jiawei Yang ,Yanji Yang ,Yan Jin ,Shi-Jie Zheng ,Hongwei Liu ,Q Q Yin ,Juan Zhang,Yi Zhang,Yongjie Zhang ,J Y Nie ,Ming-Yu Ge,Jianfeng Zhou ,Bai-Sheng Liu,Y G Zheng ,Hongmei Zhang ,Wei Li,Xiaojing Liu ,Gang Li,Wanchang Zhang ,Mei‐Hwan Wu ,Q B Yi ,M X Fu ,X L Cao ,Zhi Zhang,Mao-Shun Li,Liang Sun,Xiaofan Zhao ,Yibao Chen ,Li Chen,Zhengwei Li ,Shu Zhang,Yuanhang Zhang ,J Guan ,Gang Chen,Chengcheng Guo ,Wenzhao Zhang ,Yajun Zhu

doi:10.1088/1674-4527/21/3/70

Abstract

We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846–031 during its outburst in 2019 with the observations of Insight-HXMT, NICER and MAXI. This outburst can be classified roughly into four different states. Type-C quasi-periodic oscillations (QPOs) observed by NICER (about 0.1–6 Hz) and Insight-HXMT (about 0.7–8 Hz) are also reported in this work. Meanwhile, we study various physical quantities related to QPO frequency. The QPO rms–frequency relationship in the energy band 1–10 keV indicates that there is a turning pointing in frequency around 2 Hz, which is similar to that of GRS 1915+105. A possible hypothesis for the relationship above may be related to the inclination of the source, which may require a high inclination to explain it. The relationships between QPO frequency and QPO rms, hardness, total fractional rms and count rate have also been found in other transient sources, which can indicate that the origin of type–C QPOs is non-thermal.

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