{
  "bibcode": "2005GCN..4028....1D",
  "body": "M. De Pasquale (MSSL), J. Norris (GSFC),\nT. Kennedy (GSFC), K. Mason (PPARC), N. Gehrels\n(GSFC) on behalf of the Swift/UVOT team\n\nThe Swift/UVOT began observing the field of\nGRB050922B at 15:07:42 UT, 342 seconds after the\nBAT trigger (Hullinger et al., GCN 4019).\nThere is no detection of an optical counterpart\nin the first 100 sec exposure finding chart\ndown to a 3 sigma upper limit of V=18.7.\n\n  There is also no optical/UV counterpart\ndetected in the summed images from all filters,\ndown to the following 3 sigma magnitude upper\nlimits:\n\n  Filter  T_range(sec)  Exp(sec)  3sig UL\n\n    V      342-5997      1158     20.1\n    B      489-1720       258     20.2\n    U      474-11434      720     20.5\n    UVW1   580-7616       873     20.3\n    UVM2   446-6904      1068     20.6\n    UVW2   503-1826       258     20.1\n\nWhere T_range is the time post-trigger over which\nthe summed images were accumulated and Exp is the\ntotal exposure time. The magnitudes upper limits\nare not corrected for extinction.\n\n  These magnitudes are based on preliminary zero-\npoints, measured in orbit, and will require\nrefinements with further calibrations.",
  "circularId": 4028,
  "createdOn": 1127488146000,
  "email": "mdp@mssl.ucl.ac.uk",
  "subject": "GRB050922B: Swift UVOT early upper limits.",
  "submitter": "Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>",
  "eventId": "GRB 050922B"
}