{
  "bibcode": "2015GCN.18432....1M",
  "body": "L. M. McCauley (PSU), and A. Melandri (INAF-OAB)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 151021A\n99 s after the BAT trigger (Melandri et al., GCN Circ. 18425).\nA source consistent with the XRT position\n(Osborne et al. GCN Circ. 18428)\nis detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  22:30:34.43 = 337.64335 (deg.)\n    Dec (J2000) = -33:11:50.3  = -33.19715 (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\nsystem\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures\nare:\n\nFilter         T_start(s)   T_stop(s)   Exp(s)     Mag\n\nwhite                  99         249      294   16.89\nwhite                1668        5949      216  >20.86\nv                      81          90        9   15.82\nv                    1545        6359      235  >19.28\nb                    1644        5744      216  >20.19\nu                    1619        5538      216  >19.77\nuvw1                 5133        5333      196  >19.53\nuvm2                 4928        7484      316  >19.64\nuvw2                 5955        6155      196  >19.97\n\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.01 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 18432,
  "createdOn": 1445442272000,
  "email": "marissamc@swift.psu.edu",
  "subject": "GRB 151021A: Swift/UVOT Detection",
  "submitter": "Marissa McCaule at PSU  <marissamc@swift.psu.edu>",
  "eventId": "GRB 151021A"
}