TITLE: GCN CIRCULAR NUMBER: 12325 SUBJECT: GRB 110903A: Swift/UVOT Upper Limits DATE: 11/09/03 22:18:17 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) and K.L. Page (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110903A 33.8 ks after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 12322). No optical afterglow consistent with the enhanced XRT position (Page, GCN Circ. 12324) is detected in the initial UVOT exposures. UVOT magnitude 3-sigma upper limits are reported in the following table: Filter T_start T_stop Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- white 38935 45300 1507 > 21.94 v 39664 40380 705 > 19.86 u 33776 44483 1589 > 20.73 The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.01 (Schlegel et al. 1998). All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).