TITLE:   GCN CIRCULAR
NUMBER:  22190
SUBJECT: GRB 171205A: GOTO detection of the optical counterpart
DATE:    17/12/06 16:56:54 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@leicester.ac.uk>

D.Steeghs, R.Cutter, K.Ulaczyk, D.Pollacco, R.West, A.Levan, J.Lyman, P.Chote, J.McCormac, K.Wiersema (U. Warwick)
G.Ramsay (Armagh O.)
R.Starling, P.O'Brien, R.Eyles (U. Leicester)
D.K.Galloway, E.Rol, E.Thrane, K.Ackley, A.Casey (Monash U.)
V.Dhillon, M.Dyer, S.Littlefair, E.Daw, J.Mullaney, L.Makrygianni, J.Maund (U. Sheffield)
S.Poshyachinda, S.Aukkaravittayapun, U.Sawangwit, S.Awiphan, D.Mkrtichian (NARIT)

report on behalf of the GOTO collaboration:


The Gravitational-wave Optical Transient Observer observed the field of GRB 171205A (trigger=794972, D'Elia et al. GCN Circ. 22177) from Roque de los Muchachos Observatory beginning at 2017-12-06T04:24:31 UT, 21.07 hours since burst, in several wide-band filters.

In a combined L-band image (400-700nm passband), with a total exposure time of 1440s at a mid-time 04:57:38 UT, 21.36 hours since burst, we detect the optical counterpart (Selsing et al. GCN Circ. 22180; Emery & D'Elia GCN Circ. 22181; Butler et al. GCN Circ. 22182; Mao et al. GCN Circ. 22186; Choi & Im GCN Circ. 22188) with a preliminary magnitude of V=18.95 +/- 0.15 based on a comparison to APASS V-band calibrators. Galaxy contamination is likely leading to an additional systematic uncertainty.
An image can be viewed here: www.arm.ac.uk/~gar/GRB171205A-goto.jpg<http://www.arm.ac.uk/~gar/GRB171205A-goto.tiff>


Further observations are scheduled.

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 Astrofísica de Canarias (IAC)
(https://goto-observatory.org<https://goto-observatory.org/>)
GOTO Observatory<https://goto-observatory.org/>
goto-observatory.org
The first GOTO dome at Roque de Los Muchachos observatory on La Palma. About. The Gravitational-wave Optical Transient Observer (GOTO) is a project to identify ...