GCN Circular 33406
Subject
GRB 230307A: GECAM detection of an extremely bright burst
Date
2023-03-07T16:53:45Z (a year ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Shaolin Xiong, Chenwei Wang, Yue Huang, report on behalf of the GECAM team:
GECAM-B was triggered in-flight by the extremely bright long burst at
2023-03-07T15:44:06.650 UTC (T0), which was also observed by Fermi/GBM
(GCN 33405).
The GECAM-B ground calculated location (J2000) is:
R.A.: 28.03 [deg]
Dec.: -81.51 [deg]
Error: 1 [deg] (1-sigma, statistical only)
The systematic error of this location is estimated to be ~2 degrees.
This GECAM location is consistent with the Fermi/GBM one within error.
The GECAM-B light curve shows a roughly FRED shape with a possible
precursor, with a total duration of ~100 sec. The time-averaged spectrum
analysis on the trigger alert data shows this burst has a fluence of
about 1E-3 erg/cm2 in 20-1000 keV, which is notably high, and comparable
to GRB 130427A. We caution that this analysis is very preliminary.
Refined analysis will be reported later.
Follow-up observations are encouraged.