Insight-HXMT ToO observations of X-ray bursts of SGR J1935+2154

ATel #15698; C. K. Li, C. Cai, S. L. Xiong, M. Y. Ge, C. Z. Liu, X. B. Li, S. N. Zhang (IHEP) report on behalf of the Insight-HXMT team
on 19 Oct 2022; 14:52 UT
Credential Certification: Yu-Peng Chen (chenyp@ihep.ac.cn)

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SGR J1935+2154 has been in an active phase since early October 2022. Since 2022-10-13 04:51:43 UT, Insight-HXMT has been observing SGR J1935+2154 under a public ToO. Using different time resolutions (5, 10, 20, and 40 ms), we searched the data of Insight-HXMT/HE, ME, and LE (1-10keV/LE,10-30keV/ME, and 30-250 keV/HE_NaI). Assuming that bursts were separated at least by 1 s, Insight-HXMT detected over 200 bursts during the first two-day observation. The light curves show these bursts are typical magnetar short bursts. A burst forest of more than 60 bursts was detected from 2022-10-14T16:53 to 2022-10-14T17:41, which has also been reported by NICER and Nustar in atel #15690.

We note that Insight-HXMT was pointed to SGR J1935+2154, but unfortunately blocked by the earth during the bright radio burst detected by CHIME (atel #15681) and GBT (atel #15697) from SGR J1935+2154 and the associated bright X-ray burst detected by GECAM and HEBS (atel #15682) and Konus-Wind (atel #15686).

We caution that significant data saturation may exist and is not corrected in the standard Insight-HXMT data products, since Insight-HXMT was not designed to handle very high counting rates. We thus caution users of these data products be aware of these effects.

This result is preliminary, and additional analysis of Insight-HXMT data is in progress. Insight-HXMT has been continuously observing SGR J1935+2154 since then. Any further information on Insight-HXMT observations on SGR J1935+2154 can be obtained by writing to Dr. C.K. Li (lick@ihep.ac.cn).
The online burst list of SGR J1935+2154 detected by Insight-HXMT could be found at http://hxmten.ihep.ac.cn/bursts/734.jhtml

Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org.