[vsnet-grb-info 25579] Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27679
SUBJECT: Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
DATE:    20/05/03 12:09:44 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl at ihep.ac.cn>

C. K. Li, Y. L. Tuo, M. Y. Ge, X. B. Li, J. Y. Liao, C. Cai,
S. L. Xiong, C. Z. Liu, Y. Chen, X. L. Cao (IHEP), T. P. Li (IHEP/THU),
S. M. Jia, J. Y. Nie, F. J. Lu, L. M. Song, M. Wu, Y. P. Xu,
S. N. Zhang (IHEP), L. Lin (BNU), B. Zhang (UNLV),
report on behalf of the Insight-HXMT team:

Around the trigger time (T0=2020-04-30T21:43:00.5 UTC) of the highly
polarised radio burst event reported by FAST (ATel #13699),
Insight-HXMT was carrying out the ToO observation
of SGR 1935+2154 without any occultation by the Earth.

Within T0 +/- 50 s, no significant excess events (SNR > 3 sigma)
are found in a search of the Insight-HXMT LE (1-10 keV), ME(10-30 keV)
and HE (27-250 keV) light curves.

Assuming the same spectral
model to the X-ray counterpart that we reported in ATel #13687,
and with one second timescale (1 s) coming from the position
of SGR1935+2154, the 3-sigma fluence upper-limits are as following:

Model: wabs*Cutoffpl (nH=2.6,PhoIndex=1.44, Ecut=69.8 keV):
LE:  2.68e-09 erg cm^-2
ME:  3.45e-09 erg cm^-2
HE:  4.46e-09 erg cm^-2

Insight-HXMT will continue to observe SGR 1935+2154 with LE, ME and HE
until 2020-05-06 01:20:47 UT.

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 could be found at: http://www.hxmt.org.