{
  "bibcode": "2014GCN.16061....1S",
  "body": "M. H. Siegel (PSU) and B.-B. Zhang (UAH)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 140331A\n394 s after the BAT trigger (Zhang et al., GCN Circ. 16049).\nNo optical afterglow consistent with either the enhanced XRT position\n(Beardmore et al. GCN Circ. 16052) or the RATIR detection\n(Littlejohns et al. GCN Circ. 16050) is 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           394          543          147         >21.1\nwhite              394         8016          764         >21.9\nv                  550         7092          568         >19.7\nb                  649         7912          568         >20.8\nu                  624         7707          568         >21.1\nw1                 600         7502          563         >21.1\nm2                 575         7297          529         >20.5\nw2                 700         6887          352         >21.4\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.05 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 16061,
  "createdOn": 1396291274000,
  "email": "siegel@swift.psu.edu",
  "subject": "GRB 140331A: Swift/UVOT Upper Limits",
  "submitter": "Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>",
  "eventId": "GRB 140331A"
}