{
  "bibcode": "2017GCN.21847....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 170906A\n77 s after the BAT trigger (Siegel et al., GCN Circ. 21821).\nA source consistent with the XRT position (Siegel et al. GCN Circ. 21821)\nis detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n   RA  (J2000) =  13:35:49.20 = 203.95501 (deg.)\n   Dec (J2000) = -47:06:02.1  = -47.10057 (deg.)\nwith an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are listed\nbelow.  The afterglow appears to have brightened during the early observations and\nfaded by later orbits, confirming the analysis of Lipunov et al. (GCN Circ. 21830).\n\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite (fc)         77           227          147         16.41 +/- 0.03\nwhite              570          590           19         15.47 +/- 0.04\nwhite              744          764           19         15.65 +/- 0.05\nv                  620          639           19         14.65 +/- 0.07\nv                11125        23192          901        >19.82\nb                  545          565           20         15.59 +/- 0.06\nb                12629        12744          112        >19.63\nu                  290          539          246         15.47 +/- 0.03\nu                  694          714           19         15.47 +/- 0.08\nu                17786        18086          295        >19.82\nuvm2             15973        16873          885        >20.09\nuvw1               669          689           19         17.00 +/- 0.24\nuvw1             16880        17780          885        >20.23\nuvw2               595          615           19        >17.0\nuvw2             10219        22561         1771        >20.61\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.14 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 21847,
  "createdOn": 1504809036000,
  "email": "siegel@swift.psu.edu",
  "subject": "GRB 170906A: Swift/UVOT Detection",
  "submitter": "Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>",
  "eventId": "GRB 170906A"
}