{
  "createdOn": 1699101851231,
  "submitter": "Paul Kuin at MSSL <npkuin@gmail.com>",
  "circularId": 34941,
  "submittedHow": "email",
  "bibcode": "2023GCN.34941....1K",
  "eventId": "GRB 231104A",
  "body": "N. P. M. Kuin (UCL/MSSL) and K. L. Page (U. Leicester) report on behalf\nof the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 231104A\n91 s after the BAT trigger (Page et al., GCN Circ. 34940).  No optical\nafterglow consistent with the XRT position (Goad et al., GCN Circ. 34940)\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 first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC            91          241          147         >21.7\nu_FC               304          553          246         >20.7\nwhite               91         1709          411         >21.8\nv                  633         1758          117         >19.3\nb                  559         1684          117         >20.4\nu                  304         1659          343         >20.9\nw1                 683         1808          117         >19.7\nm2                 659          679           20         >18.6\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.156 in the direction of the burst\n(Schlegel et al. 1998).\n",
  "subject": "GRB 231104A: Swift/UVOT Upper Limits"
}