GRB 210607C

Y. Q. Zhang, C. Cai, J. C. Liu, Q. Luo, S. Xiao, 
W. C. Xue, Q. B. Yi, C. Zheng���Y. Huang, C. K. Li, 
G. Li, X. B. Li, J. Y. Liao, X. Y. Song, 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:

At 2021-06-07T21:39:20.72 (T0), Insight-HXMT/HE detected 
GRB 210607C (trigger ID: HEB210607902) in a routine search of the data, 
which also triggered INTEGRAL/SPI-ACS (TrigID 9258).

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 14.84 s measured from T0-1.77 s. 
The 1-ms peak rate, measured from T0+0.74 s, is 3517 cnts/sec. 
The total counts from this burst is 22622 counts. 
URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB210607902_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 (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 telescope. 

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.

P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat
CZTI collaboration: 

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al,
2020, arxiv:2011.07067) showed detection of a long GRB 210607C, which
was also detected by Insight-HXMT/HE (GCN #30202
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 ). 

The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak at
2021-06-07 21:39:21.5 UT. The measured peak count rate associated with
the burst is 2757 (+90, -98) cts/s above the background in the combined
data of four quadrants, with a total of 22768 (+388, -416) cts. The
local mean background count rate was 469 (+3, -3) cts/s. Using
cumulative rates, we measure a T90 of 18 (+1, -1) s. 

It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve showed multiple peaks
of emission with the strongest peak at 2021-06-07 21:39:20.1 UT. The
measured peak count rate is 2596 (+99, -112) cts/s above the background
in the combined Veto data of four quadrants, with a total of 18010
(+525, -559) cts. The local mean background count rate was 1507 (+5, -6)
cts/s. We measure a T90 of 14 (+1, -1) s from the cumulative Veto light
curve. 

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.