GRB 190331C

Q. Luo, 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, X. F. Lu,
A. M. Zhang, Y. F. Zhang, 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:

At 2019-03-31T20:12:00.100 (T0), the Insight-HXMT/HE detected
GRB 190331C(trigger ID: HEB190331841) in a routine search of the data,
which was also triggered by INTEGRAL.

The Insight-HXMT/HE light curve mainly consists of one
pulse with a duration (T90) of 0.24 s measured from T0+0.04 s.
The 1-ms peak rate, measured from T0+0.050 s, is 4679 cnts/sec.
The total counts from this burst is 315 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190331841_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record 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 telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly 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.

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a short GRB 190331C, which was also detected by Insight-HXMT/HE detection (Luo Q. et al., GCN # 24037).

The source was clearly detected in the 40-200 keV energy range. The light curve shows single peak of emission at 20:12:00.155 UT. The measured peak count rate associated with the burst is 2002 cts/s above the background in the combined data of four quadrants, with a total of 1648 cts. The local mean background count rate was 498 cts/s. Using cumulative rates, we measure a T90 of 0.16 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.