GCN 45688: GRB 260920B/EP260920b: GECAM-B detection of a burst
2026-09-22T05:31:59.630Z | rev 0
Zheng-Hang Yu, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B detected a burst GRB 260920B/EP260920b at 2026-09-20T14:11:37.000 UTC (denoted as T0). According to the GECAM-B light curves in about 70-6000 keV, this burst consists of two main episodes with multiple pulses with a T90 of 162.0 +118.0/-10.0 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn/gcn/2026/9/gecambgrb260920B.png
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).
GCN 45671: EP260920b: SVOM/VT optical observation
2026-09-21T07:46:45.625Z | rev 2
H. L. Li, Y. N. Ma, C. Wu, L. P. Xin, Y. L. Qiu, Z. H. Yao, J. R. Xu, L. J. Chen, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed ToO observation on the field of EP260920b (Ni et al., GCN 45664; Yang et al., GCN 45670). The observation started at 2026-09-21T01:24:03 UTC, about 11.3 hr after trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The optical counterpart (Liu et al., GCN 45668; García-García et al., GCN 45669) was detected in VT stacked images of both channels. The following measurements are in the AB magnitude and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Magnitude (AB)
12.14 hr VT_B 55*50 sec 22.3 +/- 0.2
12.14 hr VT_R 48*50 sec 21.5 +/- 0.1
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS.