[vsnet-grb-info 20852] GRB 180715A: GOTO optical limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22950
SUBJECT: GRB 180715A: GOTO optical limits
DATE:    18/07/15 23:27:04 GMT
FROM:    Joe Lyman at U of Warwick  <j.d.lyman at warwick.ac.uk>

J.Lyman, D.Steeghs (U. Warwick), G.Ramsay (Armagh O.), M.Dyer
(U. Sheffield), K.Ulaczyk, B.Gompertz, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, N.Tanvir (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:

In response to GRB 180715A (Ukwatta et al. GCN 22947), the
Gravitational-wave Optical Transient Observer (GOTO) observed the
field near the Swift BAT detection.

Observations started at 2018-07-15T22:37:10 UT (4.5 hours after the
burst) consisted of a set of 3x120s exposures in our wide L filter
(400-700nm). We detect the source identified by Guidorzi et al.
(GCN 22949) but note that this source appears in PanSTARRS
images of the field and in the Gaia catalogue and is thus likely to
be unrelated. We did not detect any other uncatalogued source within
the BAT localisation uncertainty. A preliminary analysis of the stacked
image was used to derive a 5-sigma upper limit of V>20.5 mag.


GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/