[vsnet-grb-info 19523] GRB 170626B: The first GRB detected by the Insight-HXMT X-ray Telescope

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21265
SUBJECT: GRB 170626B: The first GRB detected by the Insight-HXMT X-ray Telescope
DATE:    17/06/26 16:16:06 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl at ihep.ac.cn>

C. Z. Liu, X. Ma, J. Y. Liao, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), X. B. Li, S. L. Xiong, C. K. Li, Y. Huang, Y. P. Chen,
M. Y. Ge, M. Gao (IHEP), T. P. Li (IHEP/THU), G. Li, M. S. Li, H. W. Liu,
F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang, Y. H. Wang, X. Y. Wen,
M. Wu, H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

The Insight-HXMT (Hard X-ray Modulation Telescope) satellite,
was launched successfully on June 15, 2017. As one of the three
instruments onboard the Insight-HXMT, the High Energy x-ray telescope (HE)
consists of 18 detector modules with a total area of about 5000 cm2.
Each HE module is made of a NaI(Tl)/CsI(Na) PHOSWICH detector.
The CsI detectors can work as a GRB monitor in the energy range of 40 keV
to ~1000 keV in the normal operation mode, or 200 keV to ~3 MeV in the
GRB operation mode, with a large effective area up to about 2000 cm2
on average and a FoV covering nearly the whole sky unblocked by the Earth.

During the commissioning phase, at 2017-06-26T00:57:55.816 (T0),
Insight-HXMT detected the GRB 170626B (trig ID: HEB170626040)
in a routine search of the data, which was also observed by the CALET
(trig# 1182473374) and the Konus-Wind (trig time: 2017-06-26T00:58:02.21).

After comparing the measurements with CALET and Konus-Wind,
we conclude that this is the first confirmed GRB discovered by
the Insight-HXMT Telescope!

The Insight-HXMT light curve mainly consists of two pulses
with a duration (T90) of 6.3 s measured from T0+2.51 s.
The 1-second peak rate, measured from T0+6.5 s, is 4426.9 cnts/sec.
The total counts from this burst is 13784 counts.
All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV. Please note that this is the deposited energy,
rather than the incident photon energy.

URL_LC: http://newshxmt.ihep.ac.cn/images/GRB/HEB170626040_lc.jpg

The analysis results presented above are preliminary;
final results will be published elsewhere.

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 about this telescope could be found at:
http://newshxmt.ihep.ac.cn/index.php/enhome .