{
  "bibcode": "2012GCN.13725....1O",
  "body": "S. R. Oates (MSSL-UCL) and J. L. Racusin (NASA/GSFC)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 120907A\n142 s after the BAT trigger (Racusin et al., GCN Circ. 13716).\nA source consistent with the enhanced XRT position (Goad et al. GCN Circ. 13722)\nis detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n  RA  (J2000) =  04:59:00.00 =  74.75002 (deg.)\n  Dec (J2000) = -09:18:54.0  =  -9.31501 (deg.)\nwith an estimated uncertainty of 0.52 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: \n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nv                  449         6811        471         >19.5\nb                  398         567          39         19.02 +/- 0.29\nu                  142         392         246         17.67 +/- 0.08\nw1                 498         666          40         18.27 +/- 0.32\nm2                 473         1122         79         18.68 +/- 0.36\nw2                 424         642          39         18.56 +/- 0.37\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.09 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 13725,
  "createdOn": 1347045477000,
  "email": "sro@mssl.ucl.ac.uk",
  "subject": "GRB 120907A: Swift/UVOT Detection",
  "submitter": "Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>",
  "eventId": "GRB 120907A"
}