TITLE: GCN CIRCULAR NUMBER: 13095 SUBJECT: GRB 120324A: Swift/UVOT Upper Limits DATE: 12/03/24 12:36:49 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and B.-B. Zhang (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120324A 84 s after the BAT trigger (Zhang et al., GCN Circ. 13090). No optical afterglow, consistent with the XRT position (Evans et al., GCN Circ. 13093) or the uncatalogued object reported by the Liverpool Telescope (Guidorzi et al., GCN Circ. 13092), 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 84 234 147 >21.2 u_FC 297 547 246 >20.2 white 84 4917 569 >22.1 v 627 5329 294 >19.9 b 553 1510 89 >19.6 u 297 1493 324 >20.2 w1 676 5615 171 >19.9 m2 652 5534 216 >20.0 w2 603 5124 274 >20.8 The magnitudes in the table are not corrected for the significant Galactic extinction due to the reddening of E(B-V) = 1.12 in the direction of the burst (Schlegel et al. 1998).