{
  "bibcode": "2021GCN.30089....1S",
  "body": "M. H. Siegel (PSU) and S. L. Laha (GSFC/UMBC/CRESST)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 210527A\n3164 s after the BAT trigger (Laha et al., GCN Circ. 30081).\nNo optical afterglow consistent with the XRT position\n(Evans et al., GCN Circ. 30083) is detected in the initial UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC          3164         3313          147         >20.2\nwhite             3164         3932          344         >21.2\nv                 4143         4343          197         >19.4\nb                 3528         3727          197         >20.4\nu                 3322         4895          331         >20.4\nw1                4553         4753          197         >20.2\nm2                4348         4548          197         >20.0\nw2                3938         4138          197         >20.5\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.023 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 30089,
  "createdOn": 1622204546000,
  "email": "mhs18@psu.edu",
  "subject": "GRB 210527A: Swift/UVOT Observations",
  "submitter": "Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>",
  "eventId": "GRB 210527A"
}