{
  "body": "M. H. Siegel (PSU) and R. Gupta (NASA GSFC) report on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 250605A 107 s after the BAT trigger (Gupta et al., GCN Circ. 40633). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 40642) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (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           107          251          141            >20.9\nwhite             5225        11166          933            >21.41\nv                16403        17310          885            >20.07\nb                 5020         5220          196            >19.83\nu                 4815        22332          204            >19.32\nuvw1             21418        22318          885            >20.16\nuvm2             17315        18088          761            >20.44\nuvw2             11173        11858          674            >20.47\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.039 in the direction of the burst\n(Schlegel et al. 1998).",
  "bibcode": "2025GCN.40657....1S",
  "createdOn": 1749489188098,
  "eventId": "GRB 250605A",
  "circularId": 40657,
  "format": "text/plain",
  "submittedHow": "web",
  "subject": "GRB 250605A: Swift/UVOT Upper Limits",
  "submitter": "Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>"
}