TITLE: GCN CIRCULAR NUMBER: 5667 SUBJECT: GRB 060929: Swift/UVOT Optical Observations DATE: 06/09/30 13:34:39 GMT FROM: Shashi Pandey at MSSL S. B. Pandey (UCL-MSSL) and C. B. Markwardt (GSFC/UMD) report on behalf of the Swift-UVOT team: The Swift UVOT began observing the GRB 060929 field (trigger 231702), 78 seconds after the BAT trigger (GCN 5654, 5660). No new source was detected in the co-added UVOT observations down to the following 3-sigma magnitude upper limits within the refined XRT error circle (GCN 5663): Filter T_range (s) Exposure (s) 3sigma UL V 78 - 2356 950 20.71 B 678 - 2295 136 20.55 U 654 - 2271 156 20.25 W1 630 - 2247 156 19.60 M2 606 - 2223 156 19.83 W2 707 - 2333 156 19.98 White 95 - 2309 273 20.96 T_range is calculated from the time of the burst. The upper limits are not corrected for Galactic extinction E(B-V) = 0.048 along the line of sight to the burst.