{
  "bibcode": "2009GCN..9544....1C",
  "body": "P.A. Curran (UCL-MSSL) reports on behalf of the Swift/UVOT team:\n\n\nThe Swift/UVOT began settled observations of the field of GRB 090621\n123 s after the BAT trigger (Curran et al., GCN 9540). No optical\nafterglow consistent with the refined XRT position (Page et al., GCN \n9543) is detected in the initial UVOT exposures. Preliminary 3-sigma \nupper limits using the UVOT photometric system (Poole et al. 2008, \nMNRAS, 383, 627) for the first exposures are:\n\n\nFilter         T_start(s)  T_stop(s)  Exp(s)     Mag\n\nwh             123         7115       805        >21.5\nv              613         6089       333        >19.4\nb              538         6910       310        >20.5\nu              282         6705       736        >20.5\nuw1            662         6500       320        >19.8\num2            637         6295       333        >19.7\nuw2            588         5884       333        >19.9\n\n\nThe values quoted above 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": 9544,
  "createdOn": 1245587358000,
  "email": "pac@mssl.ucl.ac.uk",
  "subject": "GRB 090621: Swift/UVOT Upper Limits",
  "submitter": "Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>",
  "eventId": "GRB 090621"
}