TITLE: GCN CIRCULAR NUMBER: 43049 SUBJECT: GRB 251208D: LAST optical upper limit DATE: 25/12/09 13:50:40 GMT FROM: Ruslan Konno at Weizmann Institute of Science <ruslankonno@gmail.com> R. Konno (WIS), S. Garrappa (WIS), E. A. Zimmerman (WIS), A. Horowicz (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), D. Polishook (WIS), O. Yaron (WIS), S. Fainer (WIS), A. Krassilchtchikov (WIS), Y. M. Shani (WIS), E. Segre (WIS), A. Gal-Yam (WIS), and S. Spitzer (WIS) report on behalf of the LAST Collaboration. We report observations of GRB 251208D, detected by SVOM (Lin et al., GCN 43032). Observations were conducted with the Large Array Survey Telescope (LAST; Ofek et al. 2023, PASP 135, 5001; Ben-Ami et al. 2023, PASP 135, 5002). We observed the field of GRB 251208D using 4 divergent telescopes (each with a 7.4 deg^2 FoV) in clear band (similar to the Gaia Bp band) over 5 sequential epochs. Each epoch consists of 20x20s exposures. We began observations at 2025-12-08 17:22:15 UTC (T-T0 = 0.53h). We coadd a total of 100x20s exposure images and perform image subtraction using a reference image of the field. We do not detect any new optical source up to a limiting magnitude of 20.33 (AB) within the error region reported in Lin et al., GCN 43032. LAST is a survey telescope array of the Weizmann Astrophysical Observatory (https://www.weizmann.ac.il/wao/). View this GCN Circular online at https://gcn.nasa.gov/circulars/43049. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...