GCN Circular 21301

F. J. Lu, C. K. Li, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li,
X. B. Li, J. Y. Liao, Y. Huang, Y. H. Wang, 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, L. M. Song, W. H. Tao, H. Y. 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:

During the commissioning phase, at 2017-07-05T02:45:59.00 (T0),
Insight-HXMT detected GRB 170705A (trigger ID: HEB170705115)
in a routine search of the data, which was also observed by
the Swift/BAT (Starling et al. 2017, GCN 21289
Not found
 
 
), Fermi/GBM
(Bissaldi et al. 2017, GCN 20297
Not found
 
 
) and Konus-Wind (Svinkin et al. 2017,
GCN 21299
Not found
 
 
).

The Insight-HXMT light curve consists of single pulse
with a duration (T90) of 7.0 s measured from T0-1.30 s.
The 1-second peak rate, measured from T0+1 s, is 928.3 cnts/sec.
The total counts from this burst is 3458 counts.

All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV (record energy) in the regular mode. Only gamma-rays 
with
energy greater than about 200 keV can penetrate the spacecraft and leave
signals in the CsI detectors installed on the inside of the telescope.

URL_LC: http://www.hxmt.org/images/GRB/HEB170705115_lc.jpg

The time-averaged spectrum from T0-2 s to T0+8 s is
adequately fit by a Power Law model with spectral index = -2.16 +/- 0.10.
The energy fluence is (1.42 +/- 0.30)E-05 erg/cm^2 in 200 - 5000 keV
in this time interval.

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 it could be found at:
http://www.hxmt.org/index.php/enhome .