GECAM and HEBS detection of a short X-ray burst from SGR J1935+2154 associated with radio burst

ATel #15682; C. W. Wang, S. L. Xiong, Y. Q. Zhang, J. C. Liu, C. Zheng, W. C. Xue, W. J. Tan, S. L. Xie, Q. B. Yi, Y. Zhao, Y. Wang, C. Cai, S. Xiao, Y. Huang, X. Ma, R. Qiao, P. Wang, X. Y. Zhao, P. Zhang, X. Q. Li, X. Y. Wen, W. X. Peng, L. M. Song, S. J. Zheng, Y. Q. Du, D. Y. Guo, B. Li, X. B. Li, J. Liang, Y. Q. Lu, J. Wang, H. Wu, X. Y. Song, W. H. Yu, Z. Zhang, Z. H. An, P. Y. Feng, M. Gao, K. Gong, X. J. Liu, Y. Q. Liu, X. L. Sun, J. Z. Wang, Y. B. Xu, S. Yang, D. L. Zhang, F. Zhang, C. K. Li, G. Li, J. Y. Liao, G. Chen, F. J. Lu, S. N. Zhang (IHEP) report on behalf of GECAM and HEBS teams:
on 15 Oct 2022; 06:35 UT
Credential Certification: Yu-Peng Chen (chenyp@ihep.ac.cn)

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Both GECAM-B and HEBS (dubbed as GECAM-C) were triggered in-flight by a bright short X-ray burst at 2022-10-14T19:21:39.100 UTC (T0). The in-flight and ground localization given by both instruments are well consistent with SGR J1935+2154 within the error.

We note that this burst is associated with a bright radio burst detected by CHIME (Atel #15681). The time lag between the radio and x-ray burst is about 8 s, which is consistent with the expected dispersion time from this SGR. This time lag also resembles the value of FRB200428.

The alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message is about T0+1 minute. According to the GECAM-B and GECAM-C light curves in about 20-100 keV, this burst mainly consists of a single pulse with a duration about 250 ms.

Please note that all GECAM and HEBS results here are preliminary. Refined analysis is ongoing and will be report later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) which were funded by the Chinese Academy of Sciences (CAS) and launched on Dec 10, 2020 (Beijing Time).

HEBS is an all-sky monitor for gamma-ray transients in 10 keV to 5 MeV aboard the Space advanced technology demonstration satellite (SATech-01), which is funded and built by the Chinese Academic of Sciences, and launched on July 27, 2022. Both the payload and the science operation of HEBS are inherited from GECAM mission, thus HEBS is also called GECAM-C.