{
  "bibcode": "2020GCN.28025....1B",
  "body": "A. A. Breeveld (UCL-MSSL) and B. Sbarufatti (PSU) report on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began target-of-opportunity observations of the field of GRB 200623A 37910 s after \nthe Guano and GBM trigger (Fermi GBM team, GCN Circ. 28011; Debaunay et al., GCN Circ. 28013).\n\nNo significant new sources were found at the positions of the XRT candidate sources 1 and 3 \n(Tohuvavohu et al., GCN Circ. 28023). XRT source 2 was outside the field of view for all exposures.\n\nPreliminary 3-sigma upper limit using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. \nProc. 1358, 373) for the initial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite            37910        45836         4299         >22.4\n\nThe magnitude in the table is not corrected for the Galactic extinction due to the reddening of \nE(B-V) = 0.012 in the direction of the burst (Schlegel et al. 1998).",
  "circularId": 28025,
  "createdOn": 1593026137000,
  "email": "a.breeveld@ucl.ac.uk",
  "subject": "GRB 200623A: Swift/UVOT Upper Limits",
  "submitter": "Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>",
  "eventId": "GRB 200623A"
}