GCN Circular 39047
Subject
GRB 250127A: SVOM/VT upper limit
Date
2025-01-27T16:08:37Z (14 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
SVOM/VT team: L.P. Xin, Y. L. Qiu, H.L. Li., C. Wu, D.H. Zhao, Z.H. Yao, Y.N. Ma, X.H. Han, J. Wang, W.J.Xie, H.B. Cai，J.Y. Wei（NAOC）， J. Palmerio (CEA) and S. Vergani (obs.Paris)
report on behalf of the SVOM team:
GRB 250127A (Wu et al., GCN 39041) was observed by SVOM/VT after the automatic slew of the platform. The VT conducted observations in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously.
With the VHF and X band downlinked data, no any credible candidates were found in our single or stacked images within either the errorbox of Eclairs (Wu et al., GCN 39041), or the errorbox of source #2 detected by Swift/XRT (Swift Team,GCN 39044). The 3 sigma limits in AB magnitude were derived as follows:
---------------------------------------------------------
(t-T0)_mid(min) exptime(s) Band upperlim(3sigma)
2.5 15 VT_B 20.6
2.5 15 VT_R 20.3
78.08 23*100 VT_B 23.6
79.75 23*100 VT_R 23.4
147.38 48*100+15 VT_B 23.9
147.01 46*100+2*15 VT_R 23.7
This is consistent with the non-detection report (Turpin et al., GCN 39043).
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.