GCN Circular 40716
Subject
EP250612a: SVOM/VT optical candidate
Date
2025-06-13T02:45:04Z (3 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, Y. N. Ma, 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), Y. L. Hua (PMO, CAS), T. Zhao, Y. J. Song, J. W. Hu , W. Yuan (NAO, CAS) report on behalf of the SVOM and EP Teams:
SVOM/VT observed the field of EP250612a (Hua et al., GCN 40700) in ToO mode
in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The observation started at 2025-06-12T21:08:02 UT, about 8.67 hours after the trigger time.
One uncatalogued source, compared to Legacy Survey, was detected within FXT error circle (Hua et al., GCN 40700), RA = 229.65265, DEC = -26.76771, corresponding to:
R. A. (J2000) = 15:18:36.6
DEC. (J2000) = -26:46:03.8
Error = 0.5 arcseconds
The brightness of the candidate is derived as below :
mid-time band mag(AB) exposure
9.45 hour VT_B 22.3+/-0.1 20*70 sec
9.46 hour VT_R 21.8+/-0.1 19*70 sec
Our photometry was derived in AB magnitude and not corrected for Galactic extinction.
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.