TITLE: GCN CIRCULAR NUMBER: 7660 SUBJECT: GRB080430: Swift/UVOT observations DATE: 08/05/01 21:49:40 GMT FROM: Wayne Landsman at GSFC/SSAI W.B. Landsman (NASA/GSFC) and C. Guidorzi (INAF-OAB) report on behalf of the Swift/UVOT team The Swift/UVOT observed the field of GRB 080430 starting at 58s after the BAT trigger (Guidorzi et al., GCN 7647). We detect the afterglow in all seven UVOT filters at the position RA(J2000.0) = 11:01:14.66 DEC(J2000.0) = +51:41:08.4 with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence). This position is consistent with the enhanced XRT position (Guidorzi et al. GCN 7653) and the position reported from BOOTES obervations by Jelinek et al. (GCN 7648). The detection in the UVW2 (1950 A) filter is consistent with the redshift of ~0.76 determined from spectroscopic observations by Deugarte Postigo et al. (GCN 7650) and Cucchiara & Fox (GCN 7654). The temporal slope in the white filter out to 30400 seconds is approximately alpha = 0.23. UVOT photometry from early individual images is reported below. Filter Tmid(s) Expo(s) Magnitude ----------------------------------------------------- White 108 98 17.08 ± 0.03 White 928 98 18.23 ± 0.05 v 364 393 17.64 ± 0.06 v 1184 393 18.50 ± 0.09 b 5989 197 20.05 ± 0.21 u 5784 197 18.92 ± 0.12 w1 7014 197 18.89 ± 0.16 m2 6809 197 18.88 ± 0.22 w2 5684 197 19.24 ± 0.20 ----------------------------------------------------- These magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E{B-V} = 0.012 mag (Schlegel et al. 1998). The photometry is on the UVOT flight system described in Poole et al. (2008,MNRAS,383,627).