TITLE:   GCN CIRCULAR
NUMBER:  21274
SUBJECT: GRB 170626A: Insight-HXMT observation
DATE:    17/06/27 15:29:39 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

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

During the commissioning phase, at 2017-06-26T09:37:22.32 (T0),
Insight-HXMT detected GRB 170626A (trigger ID: HEB170626400)
in a routine search of the data, which was also observed by the Swift/BAT
(Marshall et al. 2017, GCN 21264) and the Fermi/GBM
(Hamburg et al. 2017, GCN 21266).

The Insight-HXMT light curve mainly consists of several pulses
with a duration (T90) of 12.1 s measured from T0-0.43 s.
The 1-second peak rate, measured from T0+0.5 s, is 3275.0 cnts/sec.
The total counts from this burst is 9887 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://www.hxmt.org/images/GRB/HEB170626400_lc.jpg

The time-averaged spectrum from T0-2.5s to T0+12.5 s is
adequately fit by a Power Law model with spectral index = -1.85 +/- 0.03.
The event fluence (200 -50000 keV) in this time interval is
(1.86 +/- 0.09)E-05 erg/cm^2.

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://www.hxmt.org/index.php/enhome .