TITLE:   GCN CIRCULAR
NUMBER:  24432
SUBJECT: GRB 190508A: GOTO optical search - no counterparts
DATE:    19/05/09 13:44:33 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

K.Ulaczyk(1), J.Lyman(1), D.Steeghs(1), D.Galloway(2)
K.Ackley(2), A.Obradovic(2), Y-L.Mong(2),
M.Dyer(3), V.Dhillon(3), P.O'Brien(4), G.Ramsay(5),
D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6),
E.Palle(7), K.Wiersema(1), R.Cutter(1), A.Levan(1),
T. Marsh(1), R.West(1), B.Gompertz(1), E.Stanway(1),
A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3),
S.Littlefair(3), L.Makrygianni(3), E.Daw(3), J.Maund(3),
R.Starling(4), R.Eyles(4), S.Tooke(4), U.Sawangwit(6),
D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6),
P.Irawati(6), M.Kennedy(8), R.Breton(8), D.Mata-Sanchez(8),
T.Heikkila(9), R.Kotak(9)
(1) Warwick University; (2) Monash University; (3) Univ. of Sheffield;
(4) University of Leicester; (5) Armagh Observatory & Planetarium;
(6) National Astronomical Research Institute of Thailand;
(7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester;
(9) University of Turku

report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to the Fermi trigger 579036175
(GRB 190508A; GCN #24427).

We made a series of 3 x 60 s exposures using our wide L-band filter
(400-700 nm) with five pointings covering 75.9% of the estimated sky
probability region. Two independent sky passes started on 2019 May 8
21:04 UT (1.68 hrs post-burst) and 2019 May 9 1:12 UT.

Using a difference imaging analysis with recent survey observations
of the same pointings as reference, we identify no viable
counterparts. Our mean 5-sigma detection limit was g=20.6 mag based
on PS1 catalogue calibrators.


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)