{
  "bibcode": "2019GCN.25795....1M",
  "body": "F. E. Marshall (NASA/GSFC) and A. Beardmore (U. Leicester)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 190919B\n28564 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 25788).\nNo optical afterglow consistent with the optical position\n(Bolmer, GCN Circ. 25789; Tyurina et al. GCN Circ. 25791)\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             28987        29196          206         >20.3\nv                30258        36440          225         >19.6\nb                29201        36022          301         >20.2\nu                28987        35920          301         >20.7\nw1               28564        35819          602         >20.8\nm2               30471        30737          262         >20.3\nw2               29416        36416         1204         >21.8\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.03 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 25795,
  "createdOn": 1569013105000,
  "email": "marshall@milkyway.gsfc.nasa.gov",
  "subject": "GRB 190919B: Swift/UVOT Upper Limits",
  "submitter": "Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 190919B"
}