J/A+A/548/A92ivo://CDS.VizieR/J/A+A/548/A92doi:10.26093/cds/vizier.35480092CDSKains N.Bramich D.M.Figuera Jaimes R.Arellano Ferro A.Giridhar S.,Kuppuswamy K.2017-12-22T05:33:05Z2012-11-28T11:55:07ZCDS support team

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

cds-question@unistra.frglobular-star-clustersvariable-starsccd-photometryWe present the analysis of 11 nights of V and I time-series observations of the globular cluster NGC 1904 (M 79). Using this we searched for variable stars in this cluster and attempted to refine the periods of known variables, making use of a time baseline spanning almost 8 years. We use our data to derive the metallicity and distance of NGC 1904. We used difference imaging to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derive an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Out of 13 stars previously classified as variables, we confirm that 10 are bona fide variables. We cannot detect variability in one other within the precision of our data, while there are two which are saturated in our data frames, but we do not find sufficient evidence in the literature to confirm their variability. We also detect a new RR Lyrae variable, giving a total number of confirmed variable stars in NGC 1904 of 11. Using the Fourier parameters, we find a cluster metallicity [Fe/H]_ZW_=-1.63+/-0.14, or [Fe/H]_UVES_=-1.57+/-0.18, and a distance of 13.3+/-0.4kpc (using RR0 variables) or 12.9kpc (using the one RR1 variable in our sample for which Fourier decomposition was possible).2012A&A...548A..92Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/548/A92CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch 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/548/A92https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/548/A92http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/548/A92https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/548/A92https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/548/A92http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/548/A92GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/548/A92/table43 (Data for all confirmed variable stars in NGC1904)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/548/A92/table43?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/548/A92/table43?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/548/A92/table43?GETtext/xml+votable180.050000true81.056375-24.54136110.0055555555555555566/21017https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/548/A92?format=asciidefaultJ/A+A/548/A92/table43Data for all confirmed variable stars in NGC1904LCPlot of the light curvesmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVNameVariable ID (VNN)meta.id;meta.maincharprimaryRAJ2000Right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Declination (J2000) (1)pos.eq.dec;meta.mainEp? Epoch (HJD-2450000)dtime.epochdoublenullablePer? Period (2)dtime.perioddoublenullablePer1? Amigo et al. (2011, in RR Lyrae stars, Metal-poor stars and the Galaxy, ed. A. McWilliam, 127) perioddtime.perioddoublenullablePer2? Rosino (1952MmSAI..23..101R) perioddtime.perioddoublenullable<Vmag>Intensity-weighted mean V magnitudemagphot.mag;em.opt.Vfloatn_<Vmag>[b] Note on <Vmag> (3)meta.notechar<Imag>? Intensity-weighted mean I magnitudemagphot.mag;em.opt.Ifloatnullablen_<Imag>[b] Note on <Imag> (3)meta.notecharl_Vamp[~] Limit flag on Vampmeta.code.errorcharVampAmplitude in V bandmagsrc.var.amplitudefloatl_Iamp[~] Limit flag on Iampmeta.code.errorcharIampAmplitude in I bandmagsrc.var.amplitudefloatVTypeVariable typemeta.code;src.varcharn_VType[a] Note on VType (1)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/548/A92/table2*V, I and r lightcurvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVNameVariable ID (VNN), as in table4meta.id.assoccharFilter[VIr] Observation filterobs.param;obscharHJDHeliocentric Julian datedtime.epochdoublemag.sStandard magnitudemagphot.magfloatmag.iInstrumental magnitudemagphot.magfloate_mag.iError on the magnitudemagstat.errorfloatFrefReference flux (in ADU/s)s**-1phot.flux.density;em.optdoublee_FrefError on the reference flux (in ADU/s)s**-1stat.errorfloatDFluxDifferential flux (in ADU/s)s**-1phot.flux;arith.ratiodoublee_DFluxError on the differential flux (in ADU/s)s**-1stat.errorfloatpPhotometric scale factorarith.factorfloat