{
  "bibcode": "2019GCN.25255....1S",
  "body": "D.Steeghs(1), Y-L.Mong(2), G.Ramsay(5), L.Makrygianni(3),\nM.Kennedy(8), D.Galloway(2), K.Ulaczyk(1), J.Lyman(1), K.Ackley(2),\nA.Obradovic(2), M.Dyer(3), V.Dhillon(3), P.O'Brien(4), D.Pollacco(1),\nE.Thrane(2), S.Poshyachinda(6), E.Palle(7), K.Wiersema(1),\nR.Cutter(1), T. Marsh(1), R.West(1), B.Gompertz(1), E.Stanway(1),\nA.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3), S.Littlefair(3),\nE.Daw(3), J.Maund(3), R.Starling(4), R.Eyles(4), S.Tooke(4),\nU.Sawangwit(6), D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6),\nP.Irawati(6), R.Breton(8), D.Mata-Sanchez(8), T.Heikkila(9),\nR.Kotak(9), L.Nuttall (10)\n(1) Warwick University; (2) Monash University; (3) Univ. of Sheffield;\n(4) University of Leicester; (5) Armagh Observatory & Planetarium;\n(6) National Astronomical Research Institute of Thailand;\n(7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester;\n(9) University of Turku; (10) University of Portsmouth\n\nreport on behalf of the GOTO collaboration:\n\n\nWe carried out observations with the Gravitational-wave Optical\nTransient Observer (GOTO), in response to the 190730A IceCube\nneutrino event (GCN #25225, #25241).\n\nWe obtained a series of 3x60s exposures using our wide L-band filter\n(400-700 nm) with four pointings covering the directional constraint\nreported in GCN #25225.  Two sky passes have been completed so far,\nstarting on 2019 July 31 21:16 UT and 2019 Aug 1 21:15 UT.\nOur mean 5-sigma detection limit was g=20.2 mag based on PS1\ncatalogue calibrators.\n\nImages are processed immediately after acquisition using the GOTOphoto\npipeline. Difference imaging was performed on the median of each\ntriplet of exposures using recent survey observations of the same\npointings. Source candidates were initially filtered using a trained\nclassifier and cross-matched against a variety of catalogs, including\nthe MPC and PS1. Human candidate vetting was performed on those\ncandidates identified by the classifier. The region was also visually\ninspected for any notable detections in case our classifier mis-scored\na detection. No viable optical counterpart candidates were identified.\n\nWe investigated the long-term behaviour of the FSRQ source PKS\n1502+106 that was noted to be consistent with the directional\nconstraints. Our sky survey coverage of this sources shows no notable\nsigns of activity in recent months, including our recent epochs\nfollowing the neutrino event.  These findings are consistent with the\nZTF coverage noted in Stein et al. 2019, ATEL 12974. Additional\nvisits are planned, both scheduled and as part of the sky survey, to\nmonitor any changes.\n\n\n\n=====\nGOTO is operated at the La Palma observing facilities of the\nUniversity of Warwick on behalf of a consortium including the\nUniversity of Warwick, Monash University, Armagh Observatory, the\nUniversity of Leicester, the University of Sheffield, the National\nAstronomical Research Institute of Thailand (NARIT), the University of\nPortsmouth and the Instituto de Astrofisica de Canarias (IAC)\n(https://goto-observatory.org)",
  "circularId": 25255,
  "createdOn": 1564748368000,
  "email": "dsteeghs@gmail.com",
  "subject": "IceCube 190730A: No counterpart candidates or blazar activity in GOTO observations",
  "submitter": "Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>",
  "eventId": "IceCube-190730A"
}