TITLE:   GCN CIRCULAR
NUMBER:  36017
SUBJECT: GRB 240402B: GECAM-C detection
DATE:    24/04/03 17:01:02 GMT
FROM:    Kai <wcxuemail@gmail.com>

Wang-Chen Xue, Shao-Lin Xiong, Chao Zheng, Yanqiu Zhang, and Chengkui Li,
report on behalf of the GECAM team:

GECAM-C observed a long burst, GRB 240402B at
2024-04-02T08:47:46 UTC (denoted as T0), which has been 
detected by LEIA (GCN 36016) and Konus-Wind.

According to the observation data of GECAM-C, this burst mainly consists
of two peaks with a duration (T90) of 6.55 +/- 0.52 sec (15-350 keV).

The GECAM-C localization is consistent with the LEIA localization
(GCN 36016) within the error.

The time-averaged spectrum of GECAM-C data from T0-7.0 to T0+7.0 s could be
adequately fit by a cut-off power-law with photon index alpha of -0.62 (-0.14, +0.13),
and peak energy Ep of 66 (-3, +3) keV. The corresponding burst fluence is
7.69 (-0.24, +0.25) * 10^-7 erg/cm^2 in 15-350 keV.

We note that these results are preliminary and refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor
(GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B)
launched in Dec. 2020. As the third member of GECAM constellation, 
GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. 
GECAM mission is funded by the Chinese Academy of Sciences (CAS).