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GCN Circular 22899

GRB 180704B: CALET Gamma-Ray Burst Monitor detection
2018-07-05T12:07:02Z (6 years ago)
Takanori Sakamoto at AGU <>
Y. Asaoka (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito,
H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long GRB 180704B (INTEGRAL SPI-ACS trigger 8095; Konus-Wind
trigger time on 12:36:28.83) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 12:36:29.282 UTC on 4 July 2018.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a weak precursor which starts
at T-39.5 sec and ends at T-28.2 sec followed by the main pulse
which starts at T+0.8 sec, peaks at T+8.6 sec, and ends at T+31.5 sec.
The T90 and the T50 durations measured by the SGM data are
56.5 +- 5.6 sec and 7.6 +- 0.9 sec (40-1000 keV), respectively.

The ground processed light curve is available at

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.
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