[vsnet-grb-info 25588] Insight-HXMT detection of a short bright burst from SGR 1935+2154

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27688
SUBJECT: Insight-HXMT detection of a short bright burst from SGR 1935+2154
DATE:    20/05/04 14:38:05 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl at ihep.ac.cn>

Li X.-B., Li C.-K., Xue W.-C., Ge M.-Y., Xiong S.-L.,
Jia S.-M., Nie J.-Y., Zhao H.-S., Li B.,
Lu F.-J., Song L.-M., Liu C.-Z., Chen Y., Cao X.-L., Xu Y.-P.,
Li T.-P.,  Zhang S.-N.(IHEP), Lin L. (BNU), Zhang B. (UNLV),
on behalf of the Insight-HXMT team:

During the ToO observation to SGR 1935+2154, Insight-HXMT/HE detected
a short (~0.2 s) and bright burst at 2020-05-03 23:25:13.4 UT
(satellite time), which was also detected by Fermi/GBM (trigNum 610241118)
and AGILE (GCN #27687). According to the relative rates in 17 detectors
of HE (20-250 keV), this burst is consistent as from SGR 1935+2154.

The HE light curve consists of two major bumps with a
separation time of ~50 ms, and a relatively weaker but narrower peak,
which is similar to the FRB-associated burst at 14:34:24.5 UT of April 28
(GCN 27675, Atel #13687, Atel #13696) but with a much higher peak flux.

The HE light curves have been corrected for data saturation
caused by the extreme brightness of this burst in HE.
HE detectors are divided into 3 groups, i.e. PDAU 0, PDAU 1 and PDAU 2.
Each group consists of 6 detectors and has implemented data saturation
correction separately. The Insight-HXMT/HE light curve could be found at:
http://newshxmt.ihep.ac.cn/images/grb/SGR1935_20200503T23.png

After receiving the ME (5-30 keV) and LE (1-10 keV) data, more analysis
results will be reported.