J/ApJ/848/L29ivo://CDS.VizieR/J/ApJ/848/L29doi:10.26093/cds/vizier.18489029CDSDiaz M.C.Macri L.M.Garcia Lambas D.Mendes de Oliveira C.,Nilo Castellon J.L.Ribeiro T.Sanchez B.Schoenell W.Abramo L.R.,Akras S.Alcaniz J.S.Artola R.Beroiz M.Bonoli S.Cabral J.,Camuccio R.Castillo M.Chavushyan V.Coelho P.Colazo C.,Costa-Duarte M.V.Cuevas Larenas H.DePoy D.L.Dominguez Romero M.,Dultzin D.Fernandez D.Garcia J.Girardini C.Goncalves D.R.,Goncalves T.S.Gurovich S.Jimenez-Teja Y.Kanaan A.Lares M.,Lopes de Oliveira R.Lopez-Cruz O.Marshall J.L.Melia R.Molino A.,Padilla N.Penuela T.Placco V.M.Quinones C.Ramirez Rivera A.,Renzi V.Riguccini L.Rios-Lopez E.Rodriguez H.Sampedro L.,Schneiter M.Sodre L.Starck M.Torres-Flores S.Tornatore M.,Zadrozny A.2018-09-26T10:22:06Z2018-07-16T14:33:29ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgravitational-wavesneutron-starsvisible-astronomysloan-photometryWe present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart ({Delta}g=0.17+/-0.03mag, {Delta}r=0.14+/-0.02mag, {Delta}i=0.10+/-0.03mag) over the course of only 80 minutes of observations obtained ~35hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ~59hr after the event with the EABA 1.5m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a "blue kilonova" relatively free of lanthanides.2017ApJ...848L..29Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/848/L29CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)J/ApJ/843/16 : Galaxy groups within 3500km/s (Kourkchi+, 2017)J/ApJ/848/L16 : Counterpart of GW170817. I. DECam obs. (Soares-Santos+, 2017)J/ApJ/848/L33 : Opt. follow-up of GW events with LCO (Arcavi+, 2017)J/ApJ/851/L21 : UV-NIR obs. compilation of GW170817 counterpart (Villar+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/848/L29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/848/L29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/848/L29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/848/L29https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/848/L29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/848/L29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/848/L29/table1Time-series photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTime[1.4/2.5] Time since GW triggerdtime.epochfloatBand[gir] Band in SDSS systemmeta.code;instr.filtercharmag[17.7/19.2] Apparent magnitude in Bandmagphot.magfloate_mag[0.02/0.06] Uncertainty in magmagstat.error;phot.magfloatNote[ab] Addition note (1)meta.notechar