{
  "bibcode": "2015GCN.18192....1K",
  "body": "N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf\nof the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 150821A\n251 s after the BAT trigger (Troja et al., GCN Circ. 18186).  We use the\nUVOT position as reported there which is consistent with the enhanced\nXRT position  (Goad et al. GCN Circ. 18191).\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric\nsystem (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early\nexposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite              251          401          147         16.59 +/- 0.03\nv                  560          580           20         17.21 +/- 0.18\nb                  484          504           19         17.48 +/- 0.12\nu                  460          479           19         16.70 +/- 0.11\nw1                 435          629           39         17.62 +/- 0.18\nm2                 410         7287          372        >19.8\nw2                 535         1904          156         19.85 +/- 0.28\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.02 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 18192,
  "createdOn": 1440185333000,
  "email": "npkuin@gmail.com",
  "subject": "GRB 150821A: Swift/UVOT Detection",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "GRB 150821A"
}