{
  "bibcode": "2018GCN.22937....1B",
  "body": "A. A. Breeveld (UCL-MSSL), S. W. K. Emery (UCL-MSSL) and F. E. Marshall \n(NASA/GSFC) report on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 180709A \n115 s after the BAT trigger (Marshall et al., GCN Circ. 22930).\nNo optical afterglow consistent with the XRT position (Beardmore et al., \nGCN Circ. 22933) 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 finding \nchart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite_FC           115          264          147         >20.5\nu_FC               273          523          246         >19.6\nv                  604          797           39         >18.0\nb                  529          723           39         >19.0\nuvw1               654          846           39         >17.7\n\nThe magnitudes in the table are not corrected for the Galactic \nextinction due to the reddening of E(B-V) = 2.72 in the direction of the \nburst (Schlegel et al. 1998).",
  "circularId": 22937,
  "createdOn": 1531168733000,
  "email": "a.breeveld@ucl.ac.uk",
  "subject": "GRB 180709A: Swift/UVOT Upper Limits",
  "submitter": "Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>",
  "eventId": "GRB 180709A"
}