{
  "subject": "GRB 131018A: Swift/UVOT Upper Limits",
  "eventId": "GRB 131018A",
  "bibcode": "2013GCN.15358....1D",
  "createdOn": 1382203721000,
  "circularId": 15358,
  "submitter": "Massimiliano de Pasquale at MSSL-UCL  <m.depasquale@ucl.ac.uk>",
  "email": "m.depasquale@ucl.ac.uk",
  "body": "M. De Pasquale (UCL-MSSL) and A. Melandri (INAF-OAB)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 131018A\n99 s after the BAT trigger (Melandri et al., GCN Circ. 15349).\nNo optical afterglow consistent with the XRT position\n(Goad et al. GCN Circ. 15352) is 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 first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC           120          270          147         >21.3\nu_FC               279          528          246         >20.5\nwhite              120        13702         1588         >22.4\nv                   99         7600          581         >20.3\nb                  534        19468         2174         >22.0\nu                  279        18703         2368         >21.9\nw1                 657        17790         1382         >21.3\nm2                 632         7805          568         >20.5\nw2                 584         7395          568         >20.8\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.26 in the direction of the burst\n(Schlegel et al. 1998)."
}