{
  "bibcode": "2013GCN.15433....1K",
  "body": "Paul Kuin (UCL/MSSL) and Eleonora Troja (GSFC)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began observations of the field of GRB 131031A\n39.7ks after the ground-detected BAT trigger (Cummings, GCN\nCirc. 15421). An otical afterglow candidate was reported\nby Gorosabel et al. (GCN Circ. 15426) but no optical afterglow\nconsistent with the XRT position (Gompertz et al., GCN Circ. 15423)\nis detected in the initial UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the\ninitial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite            40274        52042         1559         >21.1\nv                40825        47155          762         >20.1\nu                39724        51207         1559         >21.1\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.03 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 15433,
  "createdOn": 1383313659000,
  "email": "npkuin@gmail.com",
  "subject": "GRB 131031A: Swift/UVOT Upper Limits",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "GRB 131031A"
}