TITLE: GCN CIRCULAR NUMBER: 7611 SUBJECT: GRB080413B DATE: 08/04/13 20:38:00 GMT FROM: Samantha Oates at MSSL S. R. Oates and M. Stamatikos report on behalf of the Swift/UVOT team. The Swift/UVOT began settled observations of the field of GRB 080413B 135s after the BAT trigger (Stamatikos et al., GCN 7598). We detect the afterglow in the 7 UVOT filters at the position: RA(J2000.0) = 21:44:34.65 DEC(J2000.0) = -19:58:52.40 with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence). This position is consistent with the refined XRT position and the GROND optical position (Kruehler et al., GCN 7599). The magnitudes are reported below: Filter T_Mid(s) Expo(s) Magnitude ------------------------------------------------------- White 184 98 16.67 ± 0.02 White 740 10 17.67 ± 0.15 v 440 393 17.64 ± 0.10 v 1183 393 18.64 ± 0.22 b 727 10 18.82 ± 0.71 u 796 19 17.67 ± 0.27 w1 682 19 17.42 ± 0.27 m2 810 19 18.07 ± 0.47 w2 762 19 17.92 ± 0.36 ------------------------------------------------------- The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.04 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008,MNRAS,383,627).