TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3026 SUBJECT: GRB050215b: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/15 08:44:00 GMT FROM: Pete Roming at PSU P. Roming (PSU), K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A. Blustin (MSSL), P. Brown (PSU), P. Schady, S. Rosen, K. McGowan, M. De Pasquale (MSSL), P. Boyd (GSFC/UMBC), S. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), J. Kennea (PSU), J. Cummings (GSFC), T. Sakamoto (GSFC), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050215b (GCN 3024) on February 15, 2005 at 02:35:10 UT. We detect no source down to a magnitude of 19.5 in the V-filter for a 100 second exposure 1747s after the BAT trigger. No source was detected in the other UVOT filters. The limiting magnitudes in each of the UVOT filters are as follows: UVW2 = No source identified down to 19.2 (3-sigma) for a 10 second exposure @ 88 seconds after the burst UVM2 = No source identified down to 21.3 (3-sigma) for a 100 second exposure @ 1853 seconds after the burst UVW1 = No source identified down to 20.2 (3-sigma) for a 100 second exposure @ 1959 seconds after the burst U = No source identified down to 19.8 (3-sigma) for a 100 second exposure @ 2065 seconds after the burst B = No source identified down to 19.9 (3-sigma) for a 100 second exposure @ 2171 seconds after the burst V = No source identified down to 19.5 (3-sigma) for a 100 second exposure @ 1747 seconds after the burst We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined at a future date.