TITLE:   GCN CIRCULAR
NUMBER:  35917
SUBJECT: GRB 240312A: GECAM detection of a long burst 
DATE:    24/03/13 03:12:08 GMT
FROM:    wenlongzhang2018@163.com

Wen-Long Zhang, Shao-Lin Xiong, Xiao-Yun Zhao report on behalf of the GECAM team:

GECAM-B was triggered in-flight by a long burst, GRB 240312A, at 2024-03-12T14:02:10.550 UTC (T0). INTEGRAL/SPI-ACS was also triggered by this burst. 

According to the GECAM-B light curves, this burst shows single-pulses with a total duration of ~5 sec.

According to the in-flight software, GECAM-B localized this burst to the following position (J2000): 
Ra: 13.86 deg   	
Dec: 2.45 deg
Err: 2.74 deg (1-sigma, statistical only)

The time-averaged spectrum of GECAM-B realtime data from about T0-0.2 to T0+3.8 s could be
adequately fit by a Band function with a flux about 2.09E-6 erg/cm^2/s in 20-1000 keV. 

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in December 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).