{
  "bibcode": "2017GCN.20894....1K",
  "body": "N. P. M. Kuin (UCL-MSSL) and S. J. LaPorte (PSU) report on behalf of\nthe Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB\n170317A 87 s after the BAT trigger (LaPorte et al., GCN Circ.20885).\nA fading source consistent with the XRT position (Beardmore et al.\nGCN Circ. 20887) is detected in the initial UVOT exposures. The GRB\nafterglow was also observed by Mazaeva et al. (GCN Circ. 20886) and\nMao et al. (GCN. Circ. 20889) in the R band.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  06:12:14.82 =  93.06173 (deg.)\n    Dec (J2000) = +50:29:35.2  =  50.49310 (deg.)\nwith an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).\n\nPreliminary detections and 3-sigma upper limits using the UVOT\nphotometric system  (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)\nfor the early exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite               87          237          147         17.53 +/- 0.04\nv                  629         1597          117         18.36 +/- 0.19\nb                  554         1349           78         19.12 +/- 0.19\nu                  299          549          246         17.75 +/- 0.07\nw1                 678         7320          588         20.20 +/- 0.29\nm2                 653         7115          398        >19.8\nw2                 604         8141          607        >20.2\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.19 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 20894,
  "createdOn": 1489770057000,
  "email": "npkuin@gmail.com",
  "subject": "GRB 170317A: Swift/UVOT Detection",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "GRB 170317A"
}