TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5523 SUBJECT: GRB060904A: Swift/UVOT optical observations DATE: 06/09/04 19:26:56 GMT FROM: Samantha Oates at MSSL S.R. Oates (UCL-MSSL), D. Grupe (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 060904A at 01:04:36 on 2006-09-04, 75 s after the BAT trigger (Grupe et al., GCN 5502). No new source was detected within the XRT error circle in coadded images in any filter down to the following 3-sigma magnitude upper limits: Filter Tstart Tstop Exposure 3-sigma UL ------------------------------------------------- V 55 1888 1680 20.11 B 658 1984 97 19.85 U 634 1959 117 19.49 UVW1 610 1936 117 19.91 UVM2 586 1911 117 19.95 UVW2 687 2014 128 20.55 White 75 1997 352.2 21.69 ------------------------------------------------ These upper limits are not corrected for Galactic extinction E(B-V) = 0.018.