J/ApJ/920/152ivo://CDS.VizieR/J/ApJ/920/152doi:10.26093/cds/vizier.19200152CDSNeeley J.R.Monelli M.Marengo M.Fiorentino G.Vivas A.K.Walker A.,Gallart C.Martinez-Vazquez C.E.Bono G.Cassisi S.Marconi M.,Dall'Ora M.Sarajedini A.2024-11-06T20:23:27Z2024-03-18T06:15:07ZCDS support team

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

cds-question@unistra.frdwarf-galaxiesvariable-starsphotometryvisible-astronomyWe present the discovery of variable stars in two isolated dwarf galaxies in the outskirts of the Local Group, VV 124 and KKr 25, using observations with the Hubble Space Telescope. VV 124 hosts stellar populations with a wide range of ages (>10Gyr until the present) and therefore we find all types of classical pulsators. In VV 124, we detect a total of 771 variable stars, including 78 classical Cepheids, 10 anomalous Cepheids, one Type II Cepheid, 678 RR Lyrae stars, and four eclipsing binaries. In KKr 25, we find 25 anomalous Cepheids, 46 RR Lyrae stars, and no classical Cepheids, thus the galaxy does not have a strong young population. A comparison of the variables with evolutionary tracks suggests that both galaxies may contain an intrinsic spread in metallicity, but overall are fairly metal-poor. We also present detailed simulations, which have been designed to estimate the completeness of our variable catalog. Particularly in the cases for which the observations are not deep enough to reach the main-sequence turnoff, such as the more distant Local Group dwarf galaxies, the techniques developed here can be used together with relatively shallow color-magnitude diagrams to inform on the nature of galactic populations over the full range of ages.2021ApJ...920..152Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/920/152CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/132/1361 : RR Lyrae variables in M33 (Sarajedini+, 2006)J/ApJ/699/1742 : LCID project. I. Cetus and Tucana variables (Bernard+, 2009)J/AJ/138/184 : RR Lyrae in 2 fields in M31 spheroid (Sarajedini+, 2009)J/A+A/533/A37 : VI HST photometry of VV124 = UGC4879 (Bellazzini+, 2011)J/ApJ/751/46 : Spectroscopic observations in VV124 (UGC4879) (Kirby+, 2012)J/MNRAS/432/3047 : LCID project VIII. Cepheids of Leo A (Bernard+, 2013)J/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015)J/AcA/66/131 : VI light curves of SMC and LMC RR Lyrae (Soszynski+, 2016)J/ApJ/850/137 : ISLAndS project. III. (Martinez-Vazquez+, 2017)J/AJ/153/96 : Standard Galactic field RR Lyrae. I. Photo (Monson+, 2017)J/AcA/67/297 : OGLE Galactic center Cepheids & RR Lyrae (Soszynski+, 2017)J/AcA/68/89 : VI light curves of SMC type II Cepheids (Soszynski+, 2018)J/MNRAS/496/5039 : Updated PA and PAC relations for Cepheids (De Somma+, 2020)J/MNRAS/492/1061 : A DECam view of Crater II - Variable stars (Vivas+, 2020)J/MNRAS/500/817 : Mid-infrared catalogue for LMC & SMC Cepheids (Chown+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/920/152https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/920/152http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/920/152https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/920/152https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/920/152http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/920/152GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/920/152/table3 (Summary of variables in KKr25 and VV124)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/920/152/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/920/152/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/920/152/table3?GETtext/xml+votable180.050000true243.4770261154.387571940.0055555555555555566/7265 101532.0401237512456292e-19 4.2441532724171825e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/920/152?format=asciiOpticaldefaultJ/ApJ/920/152/table3Summary of variables in KKr25 and VV124recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalName of galaxymeta.id.parentcharStarVariable name (1)meta.id;meta.maincharClassVariable class (2)meta.code.classcharsubtypevariable mode or subclass (2)meta.code.classcharRAJ2000[138/244] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[52/55] Declination (J2000)degpos.eq.dec;meta.mainPer[0/9] log of the period in dayslog(d)time.periodfloate_Per[0.001/4]? error on the log of the periodlog(d)stat.errorfloatnullablet0[58490/58682] epoch of maximumdtime.epochdoubleF475w[21.9/27.4] mean magnitude in the f475w filtermagphot.mag;em.opt.Vfloate_F475w[0.01/0.2]? error in F475w (3)magphot.mag;em.opt.VfloatnullableF475wamp[0.1/2] amplitude in the f475w filtermagphot.mag;em.opt.Vfloate_F475wamp[0.02/0.4]? error in F475wamp (3)magphot.mag;em.opt.VfloatnullableF475wsigma[0.01/0.32] standard deviation of the residuals from template fit in f475w filtermagphot.mag;em.opt.VfloatF814w[21.9/27.4] mean magnitude in the f814w filtermagphot.mag;em.opt.Ifloate_F814w[0.01/0.09]? error in F814w (3)magphot.mag;em.opt.IfloatnullableF814wamp[0.1/1.23] amplitude in the f814w filtermagphot.mag;em.opt.Ifloate_F814wamp[0.02/0.3]? error in f814wamp (3)magphot.mag;em.opt.IfloatnullableF814wsigma[0.01/0.6] standard deviation of the residuals from template fit in f814w filtermagphot.mag;em.opt.IfloatLCInteractive Plotmeta.ref.urlcharJ/ApJ/920/152/fig3Multi-epoch photometry of all confirmed and candidate variable starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalName of galaxymeta.id.parentcharStarName of variable star (1)meta.id;meta.maincharFiltFilter of observation; F475W or F814Wobs.param;obscharMJD[58490/58685] Modified Julian date of observation JD-2400000.5dtime.epochdoubleindexedomag[20.9/28.5] Magnitude of observation in filtermagphot.magfloate_omag[0.01/0.5] Photometric uncertainty of omagmagstat.error;phot.magfloat