{
  "bibcode": "2018GCN.22638....1B",
  "body": "A. A. Breeveld (UCL-MSSL) and Z. Liu (NAOC/U. Leicester)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began observations of the field of GRB 180411A 64 s after \nthe BAT trigger (Liu et al., GCN Circ. 22630) with a settling exposure \nin the V filter. The UVOT safety circuit tripped 3.4s into the following \nUV grism exposure, most likely due to the bright star HD223128, 5.08 \narcmin from the burst position.\n\nNo optical afterglow consistent with the enhanced XRT position (Gibson \net al. GCN Circ. 22632) is seen in the 9.3s V settling exposure to a \npreliminary 3-sigma upper limit of 16.8 mag using the UVOT photometric \nsystem (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373).\n\nThe magnitude is not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 1.104 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 22638,
  "createdOn": 1523530385000,
  "email": "a.breeveld@ucl.ac.uk",
  "subject": "GRB 180411A: Swift/UVOT Upper Limit",
  "submitter": "Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>",
  "eventId": "GRB 180411A"
}