TITLE: GCN CIRCULAR NUMBER: 37373 SUBJECT: GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations DATE: 24/09/02 13:29:52 GMT FROM: Chao Wu at NAOC SVOM/C-GFT team: Chao Wu (NAOC), Zhe Kang (CHO)，Liping Xin(NAOC),Xuhui Han(NAOC),Pinpin Zhang (NAOC)，Xiaomeng Lu (NAOC), Zhenwei Li (CHO)，You Lv (CHO)，Ruosong Zhang (NAOC)，Yujie Xiao(NAOC) SVOM JSWG: Jian-Yan Wei (NAOC, China), Bertrand Cordier (CEA, F), Shuang-Nan Zhang (IHEP, CN), Stephane Basa (LAM, F), Jean-Luc Attéia (IRAP, F), Arnaud Claret (CEA, F), Zi-Gao Dai (USTC, CN), Frederic Daigne (IAP, F), Jin-Song Deng (NAOC, CN), Andrea Goldwurm (APC, F), Diego Götz (CEA, F), Xu-Hui Han (NAOC, CN), Cyril Lachaud (APC, F), En-Wei Liang (GXU, CN), Yu-Lei Qiu (NAOC, CN), Susanna Vergani (Obs.Paris, F), Jing Wang (NAOC, CN), Chao Wu(NAOC, CN), Li-Ping Xin (NAOC,CN), Bing Zhang (UNLV, CN) After taking refined analysis on the Optical Observations (Wu et al. GCN 37292), we fixed a bug in the flux calibration pipeline. We update the afterglow magnitude of GRB 240825A as following, ----------------------------------------------------------- Filter (t-T0) sec mag +/- mag_error g 65 -> 2555 13.73 +/- 0.02 -> 18.58 +/- 0.28 r 206 -> 2088 15.11 +/- 0.02 -> 17.93 +/- 0.15 i 294 -> 2162 15.14 +/- 0.02 -> 17.68 +/- 0.15 The magnitudes were calibrated using nearby PS1 stars. We apologize for any confusion caused.