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GCN Circular 24469

Subject
LIGO/Virgo S190510g: Insight-HXMT/HE updated observation
Date
2019-05-11T04:45:33Z (5 years ago)
From
Qi Luo at IHEP <luoqi@ihep.ac.cn>
Q. Luo, C. Cai, Q. B. Yi, S. Xiao, 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: 

Following up on the updated localization (GCN #24448), we have 
re-analyzed Insight-HXMT/HE data of S190510g (GCN #24451). 
The previous estimated location we used (GCN #24451) is 
RA = 190.0, Dec = 0.0 (J2000, degrees).
And the updated estimated location we used is
RA = 90.0, Dec = -34.0 (J2000, degrees).

Insight-HXMT was taking data normally around the GW trigger time
(T0=2019-05-10 02:59:39 UTC). For the preferred sky map (GCN #24448),
at T0, all of the LIGO localization region was covered 
by 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 peak 
position of the LIGO-Virgo location probability map, the 5-sigma 
upper-limits fluence (0.2 - 5 MeV, incident energy) are reported below:

Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1 s:   5.5e-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:   9.2e-08 erg cm^-2
10 s:  2.6e-07 erg cm^-2

Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s:   2.4e-07 erg cm^-2
10 s:  8.3e-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.
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