{
  "bibcode": "2018GCN.23581....1L",
  "body": "GRB 181228A: Swift/UVOT Upper Limits\n\nS. J. LaPorte (PSU) and M. J. Moss (George Washington University)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 181228A\n93 s after the BAT trigger (Moss et al., GCN Circ. 23570).\nNo optical afterglow consistent with the XRT position\n(Moss et al. GCN Circ. 23570)\nis detected in the initial UVOT exposures.\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\nwhite_FC            93          243          147         >20.4\nu_FC               305          555          246         >20.6\nwhite               93         1354          373         >21.0\nv                  634         1404           97         >19.1\nb                  561         1330           78         >20.5\nu                  305         1305          304         >20.5\nw1                 684         1280           39         >18.4\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.51 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 23581,
  "createdOn": 1546016023000,
  "email": "sjl5346@psu.edu",
  "subject": "GRB 181228A: Swift/UVOT Upper Limits",
  "submitter": "Sam LaPorte at PSU  <sjl5346@psu.edu>",
  "eventId": "GRB 181228A"
}