{
  "submittedHow": "web",
  "format": "text/plain",
  "subject": "GRB 251013C: Swift/UVOT Detection",
  "submitter": "Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>",
  "bibcode": "2025GCN.42298....1S",
  "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 251013C 0.4 ks after the Fermi/SVOM trigger (GCN Circ. 42221, Rakotondrainibe et al., GCN Circ. 42222). A bright source consistent with the XRT position (Evans et al., GCN Circ. 42232) and optical counterpart (Palmerio et al., GCN Circ. 42223, Perez-Garcia et al., GCN Circ. 42225; Konno et al., GCN Circ. 42226; Masi et al., GCN Circ. 42228; Moskvitin, GCN Circ. 42230; Gompertz et al., GCN Circ. 42231; Garnavich, GCN Circ. 42240; Watson et al., GCN Circ. 42241) is detected in the UVOT exposures.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  23:03:20.55 = 345.83562 (deg.)\n    Dec (J2000) = -00:12:36.9  =  -0.21024 (deg.)\nwith an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: \n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nu                  480         5581         1785      15.22+/-0.03\nwhite           129831       141519         2753      21.66+/-0.20\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.045 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 42298,
  "createdOn": 1760558052858,
  "eventId": "GRB 251013C"
}