TITLE: GCN CIRCULAR NUMBER: 8827 SUBJECT: GRB090118 Swift/UVOT upper limits DATE: 09/01/19 11:47:20 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began white-band observations of the field of the likely GRB candidate detected in the BAT Slew Survey (BATSS), GRB 090118 (Copete et al., GCN 8825) at 2009-01-018 20:55:35 UT, 25.3 ks after the burst. We do not detect any new source within the Swift BAT error circle (Copete et al., GCN 8825) in a co-added white-band image down to the following 5-sigma upper limit: Filter T_start T_stop Exp Mag (ks) (ks) (s) (5-sigma upper limit) ------------------------------------------------------------- white 25.3 35.3 1292 > 21.1 ------------------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.13 mag. All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).