TITLE: GCN CIRCULAR NUMBER: 13083 SUBJECT: GRB 120320A: Swift/UVOT Upper Limits DATE: 12/03/21 11:49:34 GMT FROM: Margaret Chester at PSU M. M. Chester (PSU) and C. B. Markwardt (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120320A 175 s after the BAT trigger (Markwardt et al., GCN Circ 13071). No optical afterglow consistent with the enhanced XRT position (Beardmore et al., GCN Circ 13075) or optical candidate reported by Levan et al. (GCN Circ 13077) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag White_FC 175 325 147 >20.9 White 175 11021 1435 >22.1 v 663 6181 452 >19.8 b 589 6965 416 >20.4 u 333 6796 678 >20.6 uvw1 713 6591 432 >20.4 uvm2 688 6386 432 >20.4 uvw2 639 11148 570 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).