{
  "format": "text/plain",
  "submitter": "Sam Shilling at Lancaster University <shilling.sam@gmail.com>",
  "submittedHow": "web",
  "createdOn": 1747433875571,
  "subject": "GRB 250516A: Swift/UVOT Detection",
  "body": "S. P. R. Shilling (Lancaster U.) and A. P. Beardmore (U. Leicester)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 250516A\n108 s after the BAT trigger (Beardmore et al., GCN Circ. 40467). A source\nconsistent with the enhanced XRT position (Evans et al., GCN Circ. 40468)\nis detected in the initial UVOT exposures.\n\nThe preliminary detection and 3-sigma upper limits using the UVOT photometric\nsystem (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures\nare: \n\nFilter         T_start(s)   T_stop(s)      Exp(s)        Mag\n\nwhite              108         1715          411         20.5 +/- 0.3\nv                  650         1765          136        >18.5\nb                  576         1691          117        >19.2\nu                  320         1838          362        >19.7\nw1                 699         1814          117        >18.8\nw2                 626         1741           97        >19.1\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.062 in the direction of the burst\n(Schlegel et al. 1998).",
  "eventId": "GRB 250516A",
  "bibcode": "2025GCN.40471....1S",
  "circularId": 40471
}