{
  "bibcode": "2019GCN.25952....1H",
  "body": "K. E. Heintz (Univ. of Iceland), D. B. Malesani (DTU space), and S. Moran (NOT), report on behalf of a larger collaboration:\n\nWe observed the field of the Swift-detected GRB 191004A (Cenko et al., GCN 25945) with the Nordic Optical Telescope (NOT) equipped with StanCAM. We obtained 3x300s exposures with the Bessel R filter starting at 02:10:34 UT on October 5 (i.e. 8.05 hr post-burst). We do not detect the previously reported optical afterglow (Cenko et al., GCN 25945; Lipunov et al., GCN 25944), down to a limit of R > 23.5 mag, calibrated against the photometry of nearby field stars from the USNO-B1 catalog.",
  "circularId": 25952,
  "createdOn": 1570247255000,
  "email": "keh14@hi.is",
  "subject": "GRB 191004A: NOT optical upper limits",
  "submitter": "Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14@hi.is>",
  "eventId": "GRB 191004A"
}