TITLE: GCN CIRCULAR NUMBER: 7858 SUBJECT: Swift/UVOT Observations of GRB080607 DATE: 08/06/07 21:15:59 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL/UCL) and V. Mangano (INAF-IASFPA) report on behalf of the Swift UVOT team The Swift UltraViolet/Optical Telescope (UVOT) began taking settled observations of GRB 080607 92 seconds after the initial Swift BAT trigger (Mangano et al., GCN Circ. 7847). A faint afterglow is detected in the first white and v-band finding chart exposures only at the refined uvot position of RA=194.94665, Dec=+15.91965 deg.(= 12:59:47.20 +15:55:10.74), with an accuracy of 0.5". This is consistent with the GRB being at a redshift of z=3.036, as reported in GCN Circ. 7849 (Prochaska et al.) The first white and v-band finding chart magnitudes with 1-sigma errors are given below, as well as the 3-sigma upper limits for co-added images from later observations. Filter Tmid(s) Exp(s) Magnitude/3-sig UL --------------------------------------------- wh 190.9 98.2 19.79 +/- 0.13 wh 4806.9 510.6 > 22.07 v 594.6 393.5 19.44 +/- 0.19 v 4048.5 300.2 > 20.11 b 5527.9 412.5 > 21.28 u 4934.2 432.2 > 20.93 uvw1 4934.2 432.1 > 20.80 uvm2 4745.1 432.1 > 20.57 uvw2 5745.6 358.5 > 20.83 --------------------------------------------- where Tmid is the weighted mid time of the observation. The values quoted above are on the UVOT Photometric System (Poole et al, 2008, MNRAS 383,627). They are not corrected for the expected galactic reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).