[vsnet-grb-info 23853] GRB 191004A: NOT optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25952
SUBJECT: GRB 191004A: NOT optical upper limits
DATE:    19/10/05 03:47:35 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14 at hi.is>

K. E. Heintz (Univ. of Iceland), D. B. Malesani (DTU space), and S. Moran (NOT), report on behalf of a larger collaboration:

We 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.