GCN Circular 27679

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.