J/A+A/553/A111ivo://CDS.VizieR/J/A+A/553/A111doi:10.26093/cds/vizier.35530111CDSSkottfelt J.Bramich D.M.Figuera Jaimes R.Jorgensen U.G.Kains N.,Harpsoe K.B.W.Liebig C.Penny M.T.Alsubai K.A.Andersen J.M.,Bozza V.Browne P.Calchi Novati S.Damerdji Y.Diehl C.Dominik M.,Elyiv A.Giannini E.Hessman F.Hinse T.C.Hundertmark M.Juncher D.,Kerins E.Korhonen H.Mancini L.Martin R.Rabus M.Rahvar S.,Scarpetta G.Southworth J.Snodgrass C.Street R.A.Surdej J.,Tregloan-Reed J.Vilela C.Williams A.2017-06-01T08:52:26Z2013-10-10T13:51:25ZCDS support team

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

cds-question@unistra.frglobular-star-clustersvariable-starsccd-photometryTwo previously unknown variable stars in the crowded central region of the globular cluster NGC 6981 are presented. The observations were made using the electron multiplying CCD (EMCCD) camera at the Danish 1.54m Telescope at La Silla, Chile. The two variables were not previously detected by conventional CCD imaging because of their proximity to a bright star. This discovery demonstrates that EMCCDs are a powerful tool for performing high-precision time-series photometry in crowded fields and near bright stars, especially when combined with difference image analysis.2013A&A...553A.111Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/553/A111CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/413/1275 : VrI light curves of NGC6981 variables (Bramich+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/553/A111https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/553/A111http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/553/A111https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/553/A111https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/553/A111http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/553/A111GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/553/A111/photomEMCCD time-series i+z photometry for the new variables V57 and V58 in NGC 6981recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVName[V57 V58] Variable star IDmeta.id;meta.maincharFilter[i+z] Observation filter (1)obs.param;obscharHJDHeliocentric Julian date at mid-exposuredtime.epochdoubleDFluxDifference flux (in ADU/s unit)s**-1meta.unit;phot.flux;arith.diffdoublee_DFluxDifference flux uncertainty (in ADU/s unit)s**-1stat.errorfloat