Q. Luo, C. Cai, S. Xiao, Q. B. Yi, Y. G. Zheng, Y. Huang,
C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang,
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
Insight-HXMT was taking data normally around the reported LIGO/Virgo
S190718y event (GCN #25087), trigger time 2019-07-18T14:35:12.000 UTC.
At T0, about 91% of the 90% credible region and all of the 50% credible
region of the bayestar sky map were covered by the Insight-HXMT
without occultation by the Earth.
Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are
found in a search of the Insight-HXMT/HE raw light curves.
Assuming the GW counterpart GRB with three typical GRB Band spectral
models, two typical duration timescales (1 s, 10 s) from the center
of the LIGO-Virgo location probability map (RA=305 deg, DEC=32 deg),
the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are
Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1 s: 3.2e-08 erg cm^-2
10 s: 1.5e-07 erg cm^-2
Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s: 5.7e-08 erg cm^-2
10 s: 2.8e-07 erg cm^-2
Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s: 1.8e-07 erg cm^-2
10 s: 9.4e-07 erg cm^-2
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the spacecraft.
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.