TITLE: GCN CIRCULAR NUMBER: 43589 SUBJECT: EP260131a: SVOM/VT optical observation DATE: 26/02/01 08:04:28 GMT FROM: zhyao@bao.ac.cn Z. H. Yao, C. Wu, L. P. Xin, H. L. Li, Y. N. Ma, Y. L. Qiu, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA) and S. D. Vergani (LUX-Paris Obs.) report on behalf of the SVOM/VT team. SVOM/VT performed a Target of Opportunity observation of EP260131a detected by EP/WXT (Ding et al., GCN 43574). SVOM/VT began observing the field at 2026-01-31T17:47:46.506 UTC, ~14.3 h after T0, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. With X-band data available, the optical counterpart (Li et al., GCN 43577; Álvarez et al., GCN 43578; Malesani et al., GCN 43581; Schneider et al., GCN 43582; Schneider et al., GCN 43584; Mu el al., GCN 43588) was detected in both VT_B and VT_R band within EP/WXT's (Ding et al., GCN 43574) and EP/FXT's (Wu et al., GCN 43583) error box. The position of this target is R.A., Dec. = 149.902458, -3.307450 degrees, corresponding to: R.A. (J2000) = 09:59:36.59 Dec. (J2000) = -03:18:26.82 with an uncertainty of 0.5 arcsec. The photometric measurements are as follows: mid time (h) | exposure time (s) | band | mag (AB) --------------|-------------------|------|------------- 15.50 | 40*70 | VT_B | 22.38+/-0.05 15.31 | 41*70 | VT_R | 21.70+/-0.03 Our photometry was 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/43589. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...