{
  "bibcode": "2018GCN.22464....1E",
  "body": "S.W.K. Emery (MSSL-UCL) and M. H. Siegel (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 180305A\n30621 s after the Fermi/LAT trigger (Axelsson et al., GCN Circ. 22457).\nNo optical afterglow consistent with the enhanced XRT position\n(D'Avanzo et al., GCN Circ. 22462)\nor the RATIR and Mondy detections (Troja et al., GCN Circ. 22460;\n Mazaeva et al., GCN Circ. 22463)\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) in the\ninitial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite            30808        52964          961         >21.4\nu                30621        52533         2623         >20.7\nv                30994        48392          712         >19.5\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.454 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 22464,
  "createdOn": 1520359434000,
  "email": "samuel.emery.15@ucl.ac.uk",
  "subject": "GRB 180305A: Swift/UVOT Upper Limits",
  "submitter": "Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>",
  "eventId": "GRB 180305A"
}