{
  "format": "text/plain",
  "body": "M.H. Siegel (PSU) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 250327B 1753 s after the SVOM trigger sb25032706 (GCN Circ. 39888).  A fading source consistent with the XRT position (Page et al., GCN Circ. 39895) and the optical counterpart (Moskvitin et al., GCN Circ. 39889; Xin et al., GCN Circ. 39890; O’Neill et al., GCN Circ. 39891; Lian et al., GCN Circ. 39894; Shrestha  et al., GCN Circ. 39896; Ducoin et al., GCN Circ. 39897; Perley & Bochenek; GCN Circ. 39902; Kumar et al., GCN Circ. 39904; Dennefeld et al., GCN circ. 39905; Pankov et al., GCN circ. 39906) is detected in the initial UVOT exposures.\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                 1753           2505             740          19.78+/-0.18\nu                91894         113326            2601         >21.28\n\nThe magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.018 in the direction of the burst (Schlegel et al. 1998).",
  "eventId": "GRB 250327B",
  "circularId": 40009,
  "bibcode": "2025GCN.40009....1S",
  "createdOn": 1743600725607,
  "submitter": "Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>",
  "submittedHow": "web",
  "subject": "GRB 250327B: Swift/UVOT Detection"
}