TITLE: GCN CIRCULAR NUMBER: 25337 SUBJECT: LIGO/Virgo S190814bv: no candidates from GOTO imaging observations DATE: 19/08/15 12:03:12 GMT FROM: Rhaana Starling at U of Leicester K. Ackley(2), M.Dyer(3), R.Eyles(4), D.K.Galloway(2), B.Gompertz(1), M.Kennedy(8), A.J.Levan(1), J.Lyman(1), Y-L.Mong(2), A.Obradovic(2), G.Ramsay(5), D.Steeghs(1), E.Stanway(1), R.Starling(4), K.Wiersema(1), K.Ulaczyk(1), L.Makrygianni(3), V.Dhillon(3), P.O'Brien(4), D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6), E.Palle(7), R.Cutter(1), T. Marsh(1), R.West(1), A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3), S.Littlefair(3), E.Daw(3), J.Maund(3), S.Tooke(4), U.Sawangwit(6), D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6), P.Irawati(6), R.Breton(8), D.Mata-Sanchez(8), T.Heikkila(9), R.Kotak(9), L.Nuttall (10) (1) Warwick University; (2) Monash University; (3) Univ. of Sheffield; (4) Univ. 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; (10) Univ. of Portsmouth report on behalf of the GOTO collaboration: We carried out observations with the Gravitational-wave Optical Transient Observer (GOTO) on La Palma, in response to the LIGO/Virgo gravitational wave event S190814bv triggered 2019 Aug 14 at 21:10:39 UT. We made a series of 6 x 90 s exposures using our wide L-band filter (400-700 nm) covering ~89% of the estimated sky probability region. Observations started on 2019 Aug 15 00:39 UT (3.5 hrs post-burst) and ended 2019 Aug 15 05:36 UT. Using a difference imaging analysis with recent survey observations of the same pointings as reference, we identify no viable counterparts at this time. Our mean 5-sigma detection limit was g~18.4 mag based on PS1 catalogue calibrators, and reached g=18.9 in the deepest images (the event took place near full moon). 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)