{
  "circularId": 42100,
  "bibcode": "2025GCN.42100....1S",
  "body": "S. P. R. Shilling (Lancaster U.), M. De Pasquale (Univ. Messina) and \nA. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 251003A\n79 s after the BAT trigger (Beardmore et al., GCN Circ. 42070).\n\nNo optical afterglow consistent with the enhanced XRT position (Evans\net al., GCN Circ. 42088) or those reported by other instruments (Aceituno et al., \nGCN Circ. 42072; Moreno Méndez et al., GCN Circ. 42073; Strausbaugh et al., GCN \nCirc. 42074; Worssam et al., GCN Circ. 42094), is detected in the initial UVOT \nexposures.\n\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                  79          229          147          >20.70\nu                     291          474          180          >19.78\nv                   33828        34558          711          >20.01\nb                   43530        43837          298          >20.30\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.408 in the direction of the burst\n(Schlegel et al. 1998).",
  "format": "text/plain",
  "createdOn": 1759516413568,
  "submittedHow": "web",
  "submitter": "s.shilling@lancaster.ac.uk",
  "eventId": "GRB 251003A",
  "subject": "GRB 251003A: Swift/UVOT Upper Limits"
}