J/ApJ/786/147ivo://CDS.VizieR/J/ApJ/786/147doi:10.26093/cds/vizier.17860147CDSOrdonez A.J.Yang S.-C.Sarajedini A.2018-01-23T05:57:46Z2017-07-13T15:00:08ZCDS support team

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

cds-question@unistra.frgalaxiesvariable-starsinfrared-photometryvisible-astronomyphotometryWe present the first detailed study of the RR Lyrae variable population in the Local Group dSph/dIrr transition galaxy, Phoenix, using previously obtained HST/WFPC2 observations of the galaxy. We utilize template light curve fitting routines to obtain best fit light curves for RR Lyrae variables in Phoenix. Our technique has identified 78 highly probable RR Lyrae stars (54 ab-type; 24 c-type) with about 40 additional candidates. We find mean periods for the two populations of <P_ab_>=0.60+/-0.03 days and <P_c_>=0.353+/-0.002 days. We use the properties of these light curves to extract, among other things, a metallicity distribution function for ab-type RR Lyrae. Our analysis yields a mean metallicity of <[Fe/H]>=-1.68+/-0.06 dex for the RRab stars. From the mean period and metallicity calculated from the ab-type RR Lyrae, we conclude that Phoenix is more likely of intermediate Oosterhoff type; however the morphology of the Bailey diagram for Phoenix RR Lyraes appears similar to that of an Oosterhoff type I system. Using the RRab stars, we also study the chemical enrichment law for Phoenix. We find that our metallicity distribution is reasonably well fitted by a closed-box model. The parameters of this model are compatible with the findings of Hidalgo et al. (2009ApJ...705..704H; 2013ApJ...778..103H), further supporting the idea that Phoenix appears to have been chemically enriched as a closed-box-like system during the early stage of its formation and evolution.2014ApJ...786..147Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/786/147CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/424/1113 : VI photometry in Phoenix dwarf galaxy (Battaglia+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/786/147https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/786/147http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/786/147https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/786/147https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/786/147http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/786/147GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/786/147/table3 (IDs, Positions, and Light Curve Parameters for the Probable RR Lyrae Stars within Phoenix)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/786/147/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/786/147/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/786/147/table3?GETtext/xml+votable180.050000true27.792926389-44.3963363890.005555555555555556Cone search capability for table J/ApJ/786/147/table4 (IDs, Positions, and Light Curve Parameters for the Remaining RR Lyrae Candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/786/147/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/786/147/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/786/147/table4?GETtext/xml+votable180.050000true27.8009425-44.3973966670.0055555555555555566/35206 35212https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/786/147?format=asciiInfraredOpticaldefaultJ/ApJ/786/147/table3IDs, Positions, and Light Curve Parameters for the Probable RR Lyrae Stars within PhoenixrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameRR Lyrae star candidate identifier (VNNNNN)meta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainType[ab c] RR Lyrae type (1)meta.notecharPeriodPerioddtime.periodfloatVampV band amplitudemagsrc.var.amplitude;em.opt.VfloatIampI band amplitudemagsrc.var.amplitude;em.opt.IfloatVmagMean V band magnitudemagphot.mag;em.opt.VfloatImagMean I band magnitudemagphot.mag;em.opt.IfloatlcLight curvesmeta.ref.urlcharPhotDisplay the photometry in table2meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/786/147/table4IDs, Positions, and Light Curve Parameters for the Remaining RR Lyrae CandidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameRR Lyrae star candidate identifier (VNNNNN)meta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainType[ab c] RR Lyrae type (1)meta.notecharPeriodPerioddtime.periodfloatVampV band amplitudemagsrc.var.amplitude;em.opt.VfloatIampI band amplitudemagsrc.var.amplitude;em.opt.IfloatVmagMean V band magnitudemagphot.mag;em.opt.VfloatImagMean I band magnitudemagphot.mag;em.opt.IfloatlcLight curvesmeta.ref.urlcharPhotDisplay the photometry in table2meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/786/147/table2Time-series photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLocLocation (Inner, Outer)meta.codecharNameRR Lyrae star candidate identifier (VNNNNN)meta.id;meta.maincharFilterFilter used (F555W, F814W)instr.setup;instr.filtercharHJDHeliocentric Julian Date; HJD-2451900dtime.epochdoublemagObserved magnitude in Filtermagphot.magfloate_magError in magmagstat.error;phot.magfloat