GCN Circular 41488
Subject
GRB 250821A: VLT/FORS2 Optical Observation
Event
Date
2025-08-22T08:32:30Z (7 days ago)
From
Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra@roma2.infn.it>
Via
Web form
Rosa L. Becerra (U Rome), Niccolò Passaleva (U Rome), Yu-Han Yang (U Rome) and Eleonora Troja (U Rome) report on behalf of the ERC BHianca team:
We observed the field of GRB 250821A (Dichiara et al., GCN 41462) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began 18.4 hours after the trigger and were carried out in the R filter with an average airmass of ~1.0.
We do not detect any new source at the enhanced Swift-XRT position (Beardmore et al. GCN 41472) down to the following 3-sigma limit R>26.1 AB mag calibrated with using nearby stars in the PanSTARRS PS1 DR2 catalogue (Flewelling et al. 2020) and without Galactic extinction correction.
We thank the staff at the VLT for the rapid execution of these observations.