{
  "bibcode": "2017GCN.20552....1M",
  "body": "F. E. Marshall (NASA/GSFC) and C. B. Markwardt (NASA/GSFC)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 170127A\n102 s after the BAT trigger (Markwardt et al., GCN Circ. 20538).\nNo optical afterglow consistent with the enhanced XRT position\n(Evans et al. GCN Circ. 20548)\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\nu_FC               102          351          246         >20.5\nv                  409         1533          136         >18.7\nb                  359         1632          175         >20.4\nu                  102         1607          529         >20.7\nw1                 458         1583          136         >19.4\nm2                 434         1558          136         >20.0\nw2                 385         1658          175         >20.2\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.07 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 20552,
  "createdOn": 1485557054000,
  "email": "femarsha@khamseen.gsfc.nasa.gov",
  "subject": "GRB 170127A: Swift/UVOT Upper Limits",
  "submitter": "Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>",
  "eventId": "GRB 170127A"
}