GCN Circular 40444
Subject
GRB 250512B/EP250512a: SVOM/VT optical fading
Date
2025-05-12T16:37:10Z (2 days ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
Via
Web form
L. P. Xin, H. L. Li, Y. L. Qiu, C. Wu, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), S. D. Vergani (CNRS, Obs. Paris/LUX), P. Maggi (ObAS), Y. N. Ma, D. H. Zhao (NAOC) report on behalf of the SVOM/VT Instrument Team:
The analysis with more downlinked X-band data shows that the optical counterpart (Li et al., GCN 40443) of GRB 250512B/EP250512a (Maggi et al., GCN 40439, Zhao et al., GCN 40437) has been fading to about 21.5+/-0.2 (AB) mag in VT_R mag at the mid time of 1.6 hours after the burst, with an effective time of 12*50 seconds. The decay slop is about -1.0 after the peak time (Li et al., GCN 40443).
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.