TITLE: GCN CIRCULAR NUMBER: 39941 SUBJECT: GRB 250330A: VLT/FORS2 Optical Observations DATE: 25/03/30 10:22:23 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma rosa.becerra@roma2.infn.it

Rosa Becerra (U Rome), Eleonora Troja (U Rome), Muskan Yadav (U Rome), Roberto Ricci (U Rome) report on behalf of the ERC BHianca team:

We observed the field of GRB 250330A (Cenko et al., GCN 39938) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began at T+1.25 hours after the trigger and were carried out in the R filter at an average seeing of 0.7" and airmass about 2.2.

Image subtraction against the SkyMapper Southern Survey (SMSS) Fourth Data Release (DR4) catalog (Onken et al., 2024) shows no new uncataloged source down to r~21.5 AB. Several fainter objects are visible within the XRT position (Page et al., GCN 39940), however, additional observations are required to assess their variability

We thank the staff at the VLT for the rapid execution of these observations.

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