TITLE: GCN CIRCULAR NUMBER: 37638 SUBJECT: GRB 240825A: LBT optical observations DATE: 24/09/30 14:36:08 GMT FROM: Elisabetta Maiorano at INAF <elisabetta.maiorano@inaf.it> E. Maiorano, A. Rossi, E. Palazzi (INAF-OAS), D. Paris (OA Roma), D. B. Malesani (DAWN/NBI and Radboud Univ.), and M. De Pasquale (Univ. of Messina), report on behalf of the CIBO collaboration: We observed the field of GRB 240825A (Fermi GBM team, GCN 37273; Gupta et al., GCN 37274) with the LBC camera mounted on LBT (Mt. Graham, AZ, USA) in r’ and z’ bands (45 min exposure time per filter) approximately at midtime 05:55:00 UT on 2024-09-12 (17.6 days after the burst). The optical transient (Jiang et al. GCN 37275; Dutton et al. GCN 37276; Odeh et al. GCN 37277; Zhang et al. GCN 37278; Li et al. GCN 37280; Izzo & Malesani, GCN 37287; Lipunov et al. GCN 37289; Leonini et al. GCN 37291; Wu et al. GCN 37292; Brivio et al. GCN 32795; Odeh, GCN 37299) is well detected in r’ and z’ bands. Using PSF photometry, we measure a preliminary AB magnitude of r'=22.8+-0.1, calibrated against Pan-STARRS field stars, and not corrected for the foreground Galactic extinction. We acknowledge the excellent support from the LBTO and LBTB staff, particularly Jan Snigula in obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/37638. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...