{
  "bibcode": "2023GCN.33211....1B",
  "body": "A. Belles (PSU) and M. Williams (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 230123A\n93 s after the BAT trigger (Williams et al., GCN Circ. 33206).\nNo optical afterglow consistent with the XRT position\n(Beardmore et al. GCN Circ. 33209)\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            93          243          147         >20.6\nu_FC               305          555          246         >20.6\nwhite               93         1704          412         >21.0\nv                  637         1754          136         >19.4\nb                  562         1679          117         >20.0\nu                  305         1825          359         >20.5\nw1                 686         1804          117         >20.8\nm2                1412         1605           39         >18.7\nw2                 612         1209           78         >20.1\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.022 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 33211,
  "createdOn": 1674501947000,
  "email": "aub1461@psu.edu",
  "subject": "GRB 230123A: Swift/UVOT Upper Limits",
  "submitter": "Alexander Belles at PSU/Swift  <aub1461@psu.edu>",
  "eventId": "GRB 230123A"
}