TITLE: GCN CIRCULAR NUMBER: 40021 SUBJECT: GRB 250402A: REM optical/NIR upper limits DATE: 25/04/03 09:46:37 GMT FROM: Riccardo Brivio at INAF-OAB riccardo.brivio@inaf.it
R. Brivio, M. Ferro, P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:
We observed the field of the SVOM/ECLAIRs GRB 250402A (Chen et al., GCN 40014) with the REM 60 cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, and K bands, started on 2025 April 03 at 00:50:28 UT (i.e. 1.7 hr after the burst), and lasted for about 2 hours.
From preliminary inspection, we do not find any counterpart at the position of the reported optical afterglow candidate (Xin et al., GCN. 40015; Pérez-Fournon et al., GCN 40020) down to the following 3sigma limits:
r > 20.3 (AB; calibrated against the Pan-STARRS catalogue), at a mid-time of 2.8 hours after the trigger,
H > 16.1 (Vega; calibrated against the 2MASS catalogue), at a mid-time of 2.2 hours after the trigger.
View this GCN Circular online at https://gcn.nasa.gov/circulars/40021. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...