{
  "bibcode": "2017GCN.21099....1K",
  "body": "N. P. M. Kuin (UCL-MSSL) and A. Y. Lien (GSFC/UMBC) report\non behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field\nof GRB 170516A 87 s after the BAT trigger (Lien et al., GCN Circ.\n21097). No optical afterglow consistent with the XRT position\n(Lien et al. GCN Circ. 21097) is detected in the initial\nUVOT exposures. Preliminary 3-sigma upper limits using\nthe UVOT photometric system (Breeveld et al. 2011, AIP\nConf. Proc. 1358, 373) for the first finding chart (FC)\nexposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC            87          237          147         >20.1\nwhite               87         5703          541         >21.1\nv                 4478         6113          393         >19.8\nb                 3863         5498          393         >20.6\nu                  299         5293          379         >19.4\nw1                4888         5088          197         >19.4\nm2                4683         6222          299         >20.5\nw2                4274         5909          393         >20.5\n\nThe magnitudes in the table are not corrected for the\nGalactic extinction due to the reddening of E(B-V) = 0.03\nin the direction of the burst (Schlegel et al. 1998).",
  "circularId": 21099,
  "createdOn": 1494972141000,
  "email": "npkuin@gmail.com",
  "subject": "GRB 170516A: Swift/UVOT Upper Limits",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "GRB 170516A"
}