{
  "bibcode": "2011GCN.12039....1O",
  "body": "S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 110521A\n105 s after the BAT trigger (Oates et al., GCN Circ. 12031).\nNo optical afterglow consistent with the XRT position\n(Beardmore et al., GCN Circ. 12034) is detected in the initial UVOT exposures.\n\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)\nexposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n---------------------------------------------------------------\nwhite_FC           105          255          147         >20.4\nu_FC               263          513          246         >20.0\nwhite              105         6615          766         >21.0\nv                  594        41254         2261         >20.5\nb                  519        30377         1766         >21.1\nu                  263        36155         3624         >21.7\nw1                 644        35466         3860         >22.0\nm2                 618        41934         3564         >22.3\nw2                 570        40340         2262         >22.3\n--------------------------------------------------------------\n\nThe values quoted above 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": 12039,
  "createdOn": 1306056175000,
  "email": "sro@mssl.ucl.ac.uk",
  "subject": "GRB 110521A: Swift/UVOT Upper Limits",
  "submitter": "Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>",
  "eventId": "GRB 110521A"
}