{
  "bibcode": "2015GCN.17872....1M",
  "body": "F. E. Marshall (NASA/GSFC) and A. Vargas (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 150523A\n32968 s after the LAT trigger (Bissaldi et al. GCN Circ. 17864).\nA source consistent with the XRT position (Beardmore et al. GCN Circ. 17866)\nand the optical afterglow position (Dichiara et al. GCN Circ. 17868 and 17869)\nis detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  07:41:08.67 = 115.28613 (deg.)\n    Dec (J2000) = -45:25:12.4  = -45.42011 (deg.)\nwith an estimated uncertainty of 0.78 arc sec. (radius, 90% confidence).\n\nPreliminary detections 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\nwhite            33590        39627         1150         21.83 +/- 0.24\nv                34212        40619         1433        >20.5\nu                32968        44748         2077        >20.5\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.30 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 17872,
  "createdOn": 1432660500000,
  "email": "femarsha@khamseen.gsfc.nasa.gov",
  "subject": "GRB 150523A: Swift/UVOT Detection",
  "submitter": "Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>",
  "eventId": "GRB 150523A"
}