[vsnet-grb-info 20356] GRB 180224A: OASDG optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22452
SUBJECT: GRB 180224A: OASDG optical observations
DATE:    18/02/26 10:10:08 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo at ICRA.it>

L. Izzo (IAA-CSIC), A. Noschese (AC-OASDG) report:

We observed the field of GRB 180224A (Lien et al. GCN 22442) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( http://acgo.it/oa ). 
We obtained a series of 9x180 s images in the Rc filter, starting at 23:33:36 UT, ~ 1.21 hrs after the GRB detection. In our stacked image, we find no source at the position of the observed optical counterpart (Vladimirov  et al. GCN 22444, Watson et al. GCN 22446, Mazaeva et al. GCN 22448) down to a 3-sigma limit of Rc (Vega) > 20.2.  The calibration was performed using nearby stars in the USNO B1 catalog.