{
  "bibcode": "2015GCN.18161....1M",
  "body": "L. M. McCauley (PSU), L. M. Z. Hagen (PSU), and V. D'Elia (ASDC)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 150818A\n94 s after the BAT trigger (D'Elia et al., GCN Circ. 18152).\nA source consistent with the XRT position (Beardmore et al. GCN Circ. 18159)\nis detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  15:21:25.43 = 230.35594 (deg.)\n    Dec (J2000) = +68:20:33.0  =  68.34251 (deg.)\nwith an estimated uncertainty of 0.66 arc sec. (radius, 90% confidence).\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric\nsystem (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early\nexposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite_fc            94          121           27         19.39+-0.25\nwhite             3414         4790          344         19.92+-0.17\nwhite            10222        10826          590         19.68+-0.07\nv                 3572         5201          393        >19.36\nb                 4385         4585          196        >20.16\nb                 5821        10217          927         20.56+-0.33\nu                 4180         4379          196        >19.66\nu                 5616         5816          196         19.63+-0.25\nuvw1              3976         4175          195         18.78+-0.20\nuvw1              5411         5611          196         18.95+-0.20\nuvm2              3776         3976          192         18.81+-0.23\nuvm2              5206         5406          196         18.89+-0.24\nuvw2              4796         4996          196         18.90+-0.19\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.02 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 18161,
  "createdOn": 1439930373000,
  "email": "marissamc@swift.psu.edu",
  "subject": "GRB 150818A: Swift/UVOT Detection",
  "submitter": "Marissa McCaule at PSU  <marissamc@swift.psu.edu>",
  "eventId": "GRB 150818A"
}