TITLE: GCN CIRCULAR NUMBER: 9094 SUBJECT: Swift/UVOT observations of GRB090404 DATE: 09/04/05 12:56:40 GMT FROM: Patricia Schady at MSSL/Swift S. R. Oates (MSSL-UCL) and H. Ziaeepour report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 090404 96 s after the BAT trigger (Ziaeepour et al., GCN Circ. 9086). No optical afterglow is detected in the initial UVOT exposures at the refined position of the X-ray afterglow (Beardmore et al., GCN Circ. 9088). The 3 sigma upper limits for the finding chart (fc) and summed exposures are reported below. Filter T_start (s) T_stop Exposure Mag/3UL --------------------------------------------------- white fc 96 246 147 < 20.92 white 591 1189 206 < 20.82 white 5121 18611 1084 < 21.80 u fc 310 559 246 < 20.17 u 715 1140 39 < 18.60 u 4710 35856 3049 < 21.56 v 641 1239 78 < 18.58 v 5531 11198 1150 < 20.37 b 565 1164 58 < 19.35 b 4915 35968 2078 < 21.50 uvw1 691 1116 39 < 18.45 uvw1 4504 45467 3237 < 21.47 uvm2 665 1091 58 < 18.54 uvm2 5736 41754 2695 < 21.42 uvw2 616 1214 78 < 19.09 uvw2 5326 6965 393 < 20.28 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.02 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).