TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5553 SUBJECT: GRB 060908: Swift/UVOT Observations DATE: 06/09/08 15:14:26 GMT FROM: Adam Morgan at PSU/Swift-UVOT A. N. Morgan (PSU), D. E. Vanden Berk (PSU), P. Brown (PSU) and P. A. Evans (U Leicester) report on behalf of the Swift UVOT team: The Swift/UVOT began observations of GRB 060908 at 08:58:42 UT, ~80 seconds after the initial Swift BAT trigger (Evans et al., GCN Circ. 5544). An optical counterpart was detected with the V filter at a position RA(J2000) = (02h 07m 18.36s,+00d 20' 31.2") to within 0.7". An optical afterglow was detected in the White, V, B, U, and UVW1 filters. The best estimate for the photometric redshift is z=1.62 assuming an SMC extinction law with E(B-V)=0.05, but it is poorly constrained. Values range from z=0.26-2.20 for a 90% confidence range. The photometry was performed using a 6 arcsec radius aperture and is reported below: Filter T_range(s) Exp. (s) Magnitude White 80-179 99.8 15.06 +/- 0.03 White 5839-6038 199.8 19.57 +/- 0.22 V 185-584 399.8 16.85 +/- 0.05 V 4816-6448 399.6 19.44 +/- 0.36 B 663-820 19.6 18.41 +/- 0.31 B 5635-7129 262.5 > 20.03 (3.0-sigma) U 639-658 19.7 17.01 +/- 0.16 U 786-805 19.8 17.99 +/- 0.32 UVW1 615-782 39.6 18.61 +/- 0.35 UVW1 5226-6857 399.6 > 20.24 (3.0-sigma) UVM2 591-758 39.6 > 18.57 (3.0-sigma) UVM2 5021-6652 399.6 > 20.54 (3.0-sigma) UVW2 691-858 39.6 > 19.07 (3.0-sigma) UVW2 4612-6243 399.6 > 20.71 (3.0-sigma) The values quoted above are not corrected for the expected Galactic extinction of E(B-V)=0.03.