TITLE:   GCN CIRCULAR
NUMBER:  27332
SUBJECT: GRB 200306C: GOTO upper limits
DATE:    20/03/07 00:57:36 GMT
FROM:    Kendall Ackley at Monash University  <kendall.ackley@monash.edu>

K. Ackley (1); K. Wiersema (2); Y.-L. Mong (1); D. K. Galloway (1);
D. Steeghs (2); V.Dhillon (3); P. O'Brien (4); G. Ramsay (5);
D. Pollacco (2); E. Thrane (1); S. Poshyachinda (6); R. Kotak (7);
L. Nuttall (8); E. Pall\'e (9); K. Ulaczyk (2); J. Lyman (2);
R. Cutter (2); A. Levan (2); T. Marsh (2); R. West (2); E. Stanway (2);
B. Gompertz (2);  T. Killestein (2); A. Casey (1); M. Brown (1);
B. Muller (1); M. Dyer (3); J. Mullaney (3); E. Daw (3);
S. Littlefair (3); J. Maund (3); L. Makrygianni (3); U. Burhanudin (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);
S. Mattila (7); T. Heikkil\"a (7); E. Rol (1)
((1) Monash University, (2) Warwick 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)

report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to GRB 2000306C
(Palmer et al. 2020; GCN #27326).

We made a series of 9x60 s exposures using our wide L-band filter
(400-700 nm) covering the Swift UVOT position (Palmer et al. 2020; GCN
#27326), starting at 1.1 hours after the Swift BAT trigger with
midtime 23:56:45 UT on 06 March 2020.

Using a difference imaging analysis with recent survey observations
of the same pointings as reference, we do not identify the detections
from MASTER (Lipunov et al. GCN #27324), FRAM (Jelinek et al. GCN #27328),
and BOOTES-1 (Castro-Tirado et al. GCN #27329). Our mean 5-sigma detection
limit was g=19.1 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)