{
  "bibcode": "2017GCN.20657....1S",
  "body": "M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 170208B\n127 s after the BAT trigger (Siegel et al., GCN Circ. 20632).\nNo optical afterglow consistent with the enhanced XRT position\n(Goad et al. GCN Circ. 20635) or the GROND position\n(Kruehler et al., GCN Circ. 20640)\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\nu_FC               127          377          246         >20.7\nv                  432         2146          214         >19.6\nb                  382         2096          233         >20.3\nu                  127         2211          598         >21.3\nw1                 482         2195          214         >20.1\nm2                 457         2171          214         >19.9\nw2                 408         2122          234         >19.7\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": 20657,
  "createdOn": 1486691221000,
  "email": "siegel@swift.psu.edu",
  "subject": "GRB 170208B: Swift/UVOT Upper Limits",
  "submitter": "Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>",
  "eventId": "GRB 170208B"
}