Multi-instrument Search for Gamma-Ray Counterpart of X-Ray Transients Detected by EP/WXT

• Published in: Astrophysical journal. Letters Vol. 987; no. 2; p. L38
• Main Authors: Zhang, Yan-Qiu, Xue, Wang-Chen, Zhang, Jin-Peng, Cai, Ce, Xiong, Shao-Lin, Li, Cheng-Kui, Liu, Yuan, Wang, Chen-Wei, Guo, Hao-Xuan, Xiao, Shuo, Tan, Wen-Jun, Zheng, Chao, Liu, Jia-Cong, Xie, Sheng-Lun, Zhang, Peng, Zhang, Wen-Long, Wang, Yue, Yu, Zheng-Hang, Ren, Yang-Zhao, Wang, Ping, Huang, Yue, Li, Xiao-Bo, Zhao, Xiao-Yun, Zheng, Shi-Jie, Zhang, Zhen, Yi, Shu-Xu, Song, Li-Ming, Zhang, Shuang-Nan
• Format: Journal Article
• Language: English
• Published: The American Astronomical Society 10.07.2025; IOP Publishing
• Subjects: Gamma-ray bursts; Gamma-ray observatories; X-ray transient sources
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/ade0aa

As a soft X-ray imager with an unprecedentedly large field of view, Einstein Probe (EP)/Wide-field X-ray Telescope (WXT) has detected many (fast) X-ray transients, whose nature is very intriguing. Whether there is a gamma-ray counterpart for the X-ray transient provides important implications for its origin. Some of them have been reported to be associated with gamma-ray bursts; however, a systematic study on the gamma-ray emission of these X-ray transients is lacking. In this work, we implemented a comprehensive targeted search for gamma-ray counterparts to 63 X-ray transients reported by EP/WXT during its first year of operation, using the dedicated multiple-instrument search pipeline, Energetic Transients Joint Analysis System for Multi-Instrument (ETJASMIN), with GECAM-B, GECAM-C, Fermi/GBM, and Insight-HXMT data. We find that 14 out of 63 (22%) EP/WXT X-ray transients have gamma-ray counterparts. For other transients, the ETJASMIN pipeline provided the upper limit of the gamma-ray emission, which is more stringent than that given by an individual instrument. Moreover, we investigated the properties of the X-ray transients and their gamma-ray counterparts and explored the relation between the X-ray transient and the gamma-ray counterpart.