{
  "bibcode": "2020GCN.27069....1C",
  "body": "R.Cutter (1); K.Ackley (2); B.P.Gompertz (1); J.Lyman (1);�� G.Ramsay \n(5); K.Ulaczyk (1); D.K.Galloway (2); E.Stanway (1); T.Killestein(1); \nK.Wiersema (1); M.Kennedy (10); D.Steeghs (1); M.Dyer (3); V.Dhillon \n(3); P.O'Brien (4); D.Pollacco (1); E.Thrane (2);S.Poshyachinda (6); \nS.Mattila (7); L.Nuttall (8); E.Palle (9); A.Levan (1); T.Marsh (1); \nR.West (1); Y.-L.Mong (2); A.Casey (2); M.Brown(2); B.Muller (2); \nJ.Mullaney (3); E.Daw (3); S.Littlefair (3); J.Maund (3); L.Makrygianni \n(3); R.Starling (4); R.Eyles (4); S.Tooke(4); S.Aukkaravittayapun (6); \nU.Sawangwit (6); S.Awiphan (6); D.Mkrtichian (6); P.Irawati (6); R.Kotak \n(7); T.Heikkila (7); E.Rol (2)\n\n(1) Warwick University, (2) Monash University, (3) University of \nSheffield, (4) University of Leicester, (5) Armagh Observatory & \nPlanetarium, (6) National Astronomical Research Institute of Thailand, \n(7) University of Turku, (8) University of Portsmouth, (9) Instituto de \nAstrofisica de Canarias), (10) Univ. of Manchester.\n\nreport on behalf of the GOTO collaboration:\n\nWe report on optical observations with the Gravitational-wave Optical \nTransient Observer prototype in response to S200213t (GCN #27042). \nTargeted observations started shortly after the preliminary event \nnotification was received. These spanned 47 unique tile pointings, with \nimage subtraction, containing 54.2% of the source location probability \n(based on the initial BAYESTAR skymap) and were acquired between 04:15 \nUT Feb 13 2020 and 06:44 UT Feb 14 2020 (starting 3 minutes after the \nevent trigger). No new transients that could be credibly associated with \nS200213t were detected.\n\nEach pointing spans 4.9x3.7 square degrees and consisted of 3x60s \nexposures in our L-band filter (400-700nm passband similar to g+r) with \na median 5-sigma photometric depth equivalent to g=18.4 for an \nindividual pointing (median moon illumination of 71.7% and some variable \ncloud coverage was present). Limits are based on a photometric \ncalibration against PS1 sources. Most pointings were observed multiple \ntimes, typically 2-3 times.\n\nImages are processed immediately after acquisition using the GOTOphoto \npipeline. Difference imaging was performed on the median of each triplet \nof exposures using recent survey observations of the same pointings. \nSource candidates were initially filtered using a classifier and \ncross-matched against a variety of catalogs, including the MPC and PS1. \nHuman candidate vetting was performed following data acquisition and \nautomated classifier cuts.\n\nGOTO is operated at the La Palma observing facilities of the University \nof Warwick on behalf of a consortium including the University of \nWarwick, Monash University, Armagh Observatory, the University of \nLeicester, the University of Sheffield, the National Astronomical \nResearch Institute of Thailand (NARIT), The University of Portsmouth, \nthe University of Turku and the Instituto de Astrofisica de Canarias \n(IAC) (https://goto-observatory.org/)",
  "circularId": 27069,
  "createdOn": 1581689441000,
  "email": "b.gompertz@warwick.ac.uk",
  "subject": "LIGO/Virgo S200213t: No notable candidates in GOTO imaging",
  "submitter": "Ben Gompertz at U of Warwick  <b.gompertz@warwick.ac.uk>",
  "eventId": "LIGO/Virgo S200213t"
}