{
  "bibcode": "2021GCN.30456....1S",
  "body": "M. H. Siegel (PSU) and B. Sbarufatti (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 210712A\n91 s after the BAT trigger (Sbarufatti et al., GCN Circ. 30447).\nNo optical afterglow consistent with the enhanced XRT position\n(Evans et al. GCN Circ. 30453) 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            91          241          147         >19.5\nu_FC               304          554          246         >19.6\nwhite               91          604          167         >19.5\nb                  560          579           19         >18.0\nu                  304          554          246         >19.6\nw2                 609          614            4         >17.5\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.076 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 30456,
  "createdOn": 1626131527000,
  "email": "mhs18@psu.edu",
  "subject": "GRB 210712A: Swift/UVOT Upper Limits",
  "submitter": "Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>",
  "eventId": "GRB 210712A"
}