TITLE: GCN CIRCULAR NUMBER: 38576 SUBJECT: GRB 241215A: Nanshan/HMT optical upper limit DATE: 24/12/16 01:31:20 GMT FROM: Dong Xu at NAOC/CAS <dxu@nao.cas.cn> X. Liu, S.Q. Jiang, J. An, S.Y. Fu, Z.P. Zhu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report on behalf of a large collaboration: We observed the field of GRB241215A detected by INTEGRAL/IBIS (Mereghetti et al., GCN 38573) using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 2024-12-15T16:09:56.00, i.e., ~ 2.28 hrs after the INTEGRAL trigger and consisted of 15 x 90 s frames without any filter. No uncatalogued optical source is detected in our stacked images within the INTEGRAL/IBIS 2.5 arcmin error circle (Mereghetti et al., GCN 38573), down to a 3 sigma upper limit of r ~ 19.8, calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38576. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...