TITLE: GCN CIRCULAR NUMBER: 10302 SUBJECT: GRB 091230: Swift/UVOT Observations DATE: 09/12/31 18:50:34 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and H. A. Krimm (CRESST/GSFC/USRA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 091230 32291 s after the Integral detection (Gotz et al., GCN Circ. 10298). We do not detect the afterglow reported by GROND (Filgas et al., GCN Circ. 10299) and Swift-XRT (Beardmore et al., GCN Cic. 10300). Preliminary 3-sigma upper limits are: FILTER T_start(s) T_stop Exposure Mag/3UL ============================================================= white 32291 42824 3898 >22.2 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.36 (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).