TITLE:   GCN CIRCULAR
NUMBER:  27304
SUBJECT: GRB 200303A: GOTO observations upper limit
DATE:    20/03/03 12:21:44 GMT
FROM:    Ben Gompertz at U of Warwick  <b.gompertz@warwick.ac.uk>

Y.-L. Mong (1); K. Ackley (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); K. Wiersema (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 2000303A (Cenko et al. 
2020; GCN #27297; Fermi GBM; GCN #27294).

We made a series of 3 x 60 s exposures using our wide L-band filter 
(400-700 nm) covering the Swift XRT position (Cenko et al. 2020; GCN 
#27297), starting at 6.4 minutes after the Swift BAT trigger with 
midtime 02:52:17 UT on 03 March 2020.

Using a difference imaging analysis with recent survey observations of 
the same pointings as reference, we identify no viable afterglow 
candidate. Our mean 5-sigma detection limit was g=19.6 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)