{
  "bibcode": "2016GCN.19123....1M",
  "body": "F. E. Marshall (NASA/GSFC) and D. Malesani (DARK/NBI)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 160228A\n83 s after the BAT trigger (Malesani et al., GCN Circ. 19107).\nNo optical afterglow consistent with the XRT position\n(Beardmore et al. GCN Circ. 19110) or the\nposition of the GROND optical afterglow candidate\n(Delvaux et al. GCN Circ. 19114)\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) exposures and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC            83          233          147         >20.2\nu_FC               296          546          246         >19.5\nwhite               83        10111          342         >20.5\nv                  625         5975          236         >19.0\nb                  551         6695          138         >19.8\nu                  296         6589          462         >20.2\nw1                 675         6385          235         >19.8\nm2                 650         6179          236         >19.9\nw2                 601         5770          235         >19.8\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.06 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 19123,
  "createdOn": 1456786224000,
  "email": "femarsha@khamseen.gsfc.nasa.gov",
  "subject": "GRB 160228A: Swift/UVOT Upper Limits",
  "submitter": "Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>",
  "eventId": "GRB 160228A"
}