{
  "format": "text/plain",
  "submitter": "Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>",
  "createdOn": 1743606773986,
  "body": "M.H. Siegel (PSU) and R. Caputo (GSFC) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 250329A 6.8ks after the SVOM trigger sb25032901 (Wang et al., GCN Circ. 39916). We do not detect an afterglow at the position of the XRT counterpart (Dichiara et al., GCN Circ. 39924) or optical-infrared counterparts (Watson et al., GCN Circ. 39915; Want et al., GCN Circ. 39917; Ghosh et al., GCN Circ. 39922). The lack of detection in the u-band for this bright burst would be consistent with the redshift of z=2.9 reported by Schneider et al. (GCN Circ. 39918).\n\nPreliminary detections and 3-sigma upper limits for the early exposures are:\n\nFilter\t\tT_start(s)\tT_stop(s)\tExp(s)\t\tMag(AB)\nu                 6812           13135          1551            >20.95\n\nThe magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.021 in the direction of the burst (Schlegel et al. 1998).",
  "bibcode": "2025GCN.40010....1S",
  "eventId": "GRB 250329A",
  "subject": "GRB 250329A: Swift/UVOT Upper Limit",
  "submittedHow": "web",
  "circularId": 40010
}