TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3880 SUBJECT: GRB050824: CORRECTION to UVOT observing times DATE: 05/08/25 19:00:58 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL/PSU), R. Fink (GSFC), M. Ivanushkina (PSU), S. Holland (GSFC/USRA), K. McGowen (MSSL), N. Gehrels (GSFC) on behalf of the Swift UVOT team CORRECTION: The mid time and exposure durations previously reported for observations made by Swift/UVOT of GRB050824 are incorrect (Schady et al. GCN 3878). The correct times are given below. The Swift Ultra-Violet/Optical Telescope (UVOT) observations began at 00:53:49 UT, 1.8 hrs after the BAT trigger. UVOT detects a fading source at a position consistent with that reported by Gorosabel et al. (GCN 3865) in 5 of its 6 filters. The magnitudes or 3-sigma upper limit in the first exposure taken in each filter are as follows: Filter Mid Time (hrs) Exp (s) Mag/3-sig UL V 1.8 900 20.02+/-0.39 B 5.1 900 20.88+/-0.36 U 3.6 545 19.55+/-0.32 W1 3.4 900 19.85+/-0.33 M2 2.1 532 19.34+/-0.36 W2 7.8 1457 > 20.79 The afterglow has faded below 2-sigma above background 11hrs after the burst trigger in all filters apart from the V and U, where it is still detected at the 2.3-sigma and >3-sigma level, respectively. The magnitudes have not been corrected for extinction. The reddening in this direction is E_{B-V} = 0.04mag. These magnitudes are based on preliminary zero-points, measured in orbit, and will require refinement with further calibration.