{
  "bibcode": "2010GCN.10368....1S",
  "body": "R.L.C. Starling (U Leicester), E.A. Hoversten (PSU) and F.E.\nMarshall (NASA/GSFC) report on behalf of the Swift XRT and \nUVOT teams:\n\nWe observed the Swift GRB 100203A, detected in ground analysis \n(Cummings et al. GCN Circ. 10360), with Swift XRT and UVOT \nbeginning 25.66 hours (92.3 ks) after the BAT trigger (#411011). \n\nThe XRT observed the field for 3.85 ks. No source has been detected at \nthe 3-sigma confidence level or above, with a 3-sigma upper limit on the \ncount rate at the BAT position of 6 x 10^-3 ct s^-1. We note that this \nsource lies near the Galactic Plane, where Galactic absorption in this \ndirection is high, at 5.3 x 10^21 cm^-2.\n\nThe UVOT observed the field of GRB 100203A in the uvm2 filter.\nVisual comparison with DSS images of the field reveal no afterglow\ncandidates. Given the low Galactic latitude, afterglow detection\nis complicated by high extinction and numerous bright stars in the\nfield.\n\nThe observed 3-sigma upper limits using the UVOT photometric system\n(Poole et al. 2008, MNRAS, 383, 627) for initial exposures are:\n\nFilter   T_start(s)   T_stop(s)   Exp(s)   3-sigma upper limit\n=============================================================\nuvm2       92604       103268      3915         > 21.27\n\nThe values quoted above are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.55 in the direction of the burst\n(Schlegel et al. 1998).\n\nThis circular is an official product of the Swift team.",
  "circularId": 10368,
  "createdOn": 1265388271000,
  "email": "rlcs1@star.le.ac.uk",
  "subject": "GRB 100203A: Swift XRT and UVOT refined analyses",
  "submitter": "Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>",
  "eventId": "GRB 100203A"
}