{
  "createdOn": 1702807414804,
  "body": "N. P. M. Kuin (UCL-MSSL) and Sbarrato (INAF-OAB)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 231216A\n191 s after the BAT trigger (Sbarrato et al., GCN Circ. 35378).\nNo optical afterglow consistent with the XRT position was detected\nin the initial UVOT exposures.\n\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nu_FC               191          441          246         >20.2\nv                  497          814           58         >18.5\nb                  447         1028           63         >20.0\nu                  191         1018          432         >20.8\nw1                 546          864           58         >19.5\nm2                 819          839           19         >18.3\nw2                 473          790           58         >19.6\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.082 in the direction of the burst\n(Schlegel et al. 1998).\n",
  "submitter": "Paul Kuin at MSSL <npkuin@gmail.com>",
  "eventId": "GRB 231216A",
  "circularId": 35388,
  "subject": "GRB 231216A: Swift/UVOT Upper Limits",
  "bibcode": "2023GCN.35388....1K",
  "submittedHow": "email"
}