{
  "bibcode": "2020GCN.27182....1M",
  "body": "F. E. Marshall (NASA/GSFC) and T. N. Ukwatta (LANL)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 200224A\n101 s after the BAT trigger (Ukwatta et al., GCN Circ. 27173).\nA source consistent with the enhanced XRT position\n(Gropp et al., GCNC 27179) and the optical positions reported\nby Sota et al. (GCNC 27176) and Stecklum et al. (GCNC 27177)\nis detected in the initial UVOT exposures.\nThe source is very close to the edge of the image in the\nfirst exposure at 101 s after the BAT trigger, and further\nanalysis is required to determine an accurate intensity\nfor that exposure.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  16:35:04.14 = 248.76727 (deg.)\n    Dec (J2000) = +41:36:42.3  =  41.61174 (deg.)\nwith an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nu                  259          509          246         18.75 +/- 0.10\nwhite              861         1011          147         20.57 +/- 0.20\nw1                5978        19265         1098        >20.7\nm2                5772        18542         1279        >21.4\nw2                5363        30092         1953        >21.9\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.005 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 27182,
  "createdOn": 1582580415000,
  "email": "marshall@milkyway.gsfc.nasa.gov",
  "subject": "GRB 200224A: Swift/UVOT Detection",
  "submitter": "Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 200224A"
}