TITLE: GCN CIRCULAR NUMBER: 10499 SUBJECT: GRB100316A: Swift/UVOT Upper Limits DATE: 10/03/16 14:30:44 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and W. H. Baumgartner (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 100316A 3201s after the BAT trigger (Baumgartner et al., GCN Circ. 10484). We do not detect any source at the enhanced Swift XRT position (Evans et al. GCN Circ. 10490) and at the location of the candidate source detected by the CAHA telescope (Gorosabel et al. GCN Circ. 10487). The 3-sigma upper limits for the finding chart exposures (FC) and summed images are: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- white (FC) 3201 3350 147 > 21.08 white 3770 5408 393 > 21.32 v 4182 16726 1210 > 20.48 b 3565 5203 393 > 20.79 u 3359 11527 1110 > 20.66 uvw1 4593 10786 1082 > 21.11 uvm2 4387 17306 1648 > 21.11 uvw2 3977 15812 1279 > 21.28 ------------------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.03 mag. All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).