TITLE:   GCN CIRCULAR
NUMBER:  26853
SUBJECT: GRB 200122A: GOTO non-detection of optical afterglow
DATE:    20/01/22 13:31:25 GMT
FROM:    Joe Lyman at U of Warwick  <j.d.lyman@warwick.ac.uk>

K.Wiersema (1); D.Steeghs (1); K.Ulaczyk (1); J.Lyman (1); R.Cutter
(1); T.Killestein (1); M.Dyer (3); M.Kennedy (10); G.Ramsay (5);
D.K.Galloway (2); V.Dhillon (3); P.O’Brien (4); D.Pollacco (1);
E.Thrane (2); S.Poshyachinda (6); S.Mattila (7); L.Nuttall (8);
E.Palle (9); A.Levan (1); T.Marsh (1); R.West (1); E.Stanway (1);
B.Gompertz (1); J.McCormac (1); P.Strom (1); K.Ackley (2);
Y.-L.Mong (2); A.Casey (2); M.Brown (2); B.Muller (2);
J.Mullaney (3); E.Daw (3); S.Littlefair (3); J.Maund (3);
L.Makrygianni (3); R.Starling (4); R.Eyles (4); S.Tooke (4);
S.Aukkaravittayapun (6); U.Sawangwit (6); S.Awiphan (6);
D.Mkrtichian (6); P.Irawati (6); R.Kotak (7); T.Heikkila (7); E.Rol
(2)
(1) Warwick University, (2) Monash University, (3) University of
Sheffield, (4) University of Leicester, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of
Thailand, (7) University of Turku, (8) University of Portsmouth, (9)
Instituto de Astrofisica de Canarias), (10) Univ. of Manchester.

report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to GRB 200122A
(Sonbas et al. 2020; GCN #26844).

We made a series of 3 x 60 s exposures using our wide L-band filter
(400-700 nm) covering the Swift XRT position RA, Dec = 210.01807,
+27.54884 (Osborne et al. 2020; GCN #26846), with midtime 02:35:49
UT on 22 January 2020 (3289 seconds after trigger).

Using a difference imaging analysis with recent survey observations
of the same pointings as reference, we identify no viable
afterglow candidate. Our 5-sigma detection limit was g=19.5 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)