TITLE: GCN CIRCULAR NUMBER: 44557 SUBJECT: GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope DATE: 26/05/11 16:10:48 GMT FROM: lijj328@mail2.sysu.edu.cn Jin-Ji Li, Chun Chen, Duo-Le Cao, Zhong-Nan Dong, Wei-Sen Huang, Jia-Qi Lin, Pu Lin, Yun Shi, Hao-Nan Yang, Yan Yu, P H Thomas Tam, Rong-Feng Shen, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm infrared telescope team: We observed the field of GRB 260511B (SVOM burst-id sb26051102) detected by SVOM/ECLAIRs (Godet et al., GCN 44543) and Fermi (Fermi GBM team, GCN 44542), using the Sun Yat-sen University (SYSU) 80 cm infrared telescope. Our observations started on 2026 May 11 at 13:51 UT, 2.9 hours after the GRB trigger, with a total exposure time of 1800 s in the J-band images. We clearly detect the source at the position of the optical counterpart (Wu et al., GCN 44547; Sasada et al., GCN 44549; Jiang et al., GCN 44551; Wu et al., GCN 44552), and we measure J = 16.02 +/- 0.07 Vega mag. The photometry was calibrated against nearby stars from the 2MASS catalog and is reported in the Vega system, without correction for Galactic extinction. Further observations are planned. The SYSU 80 cm infrared telescope is operated and managed by the Department of Astronomy, Sun Yat-sen University. View this GCN Circular online at https://gcn.nasa.gov/circulars/44557. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...