J/ApJ/784/76ivo://CDS.VizieR/J/ApJ/784/76doi:10.26093/cds/vizier.17840076CDSYang S.-C.Wagner-Kaiser R.Sarajedini A.Kim S.C.Kyeong J.2017-07-05T06:59:52Z2016-08-08T12:50:28ZCDS support team

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

cds-question@unistra.frgalaxiesvariable-starsinfrared-photometryvisible-astronomyphotometryWe present the results of our analysis of the RR Lyrae (RRL) variable stars detected in two transition-type dwarf galaxies (dTrans), ESO294-G010 and ESO410-G005 in the Sculptor group, which is known to be one of the closest neighboring galaxy groups to our Local Group. Using deep archival images from the Advanced Camera for Surveys on board the Hubble Space Telescope, we have identified a sample of RRL candidates in both dTrans galaxies (219 RRab (RR0) and 13 RRc (RR1) variables in ESO294-G010; 225 RRab and 44 RRc stars in ESO410-G005). The metallicities of the individual RRab stars are calculated via the period-amplitude-[Fe/H] relation derived by Alcock et al. This yields mean metallicities of <[Fe/H]>_ESO294_=-1.77+/-0.03 and <[Fe/H]>_ESO410_=-1.64+/-0.03. The RRL metallicity distribution functions (MDFs) are investigated further via simple chemical evolution models; these reveal the relics of the early chemical enrichment processes for these two dTrans galaxies. In the case of both galaxies, the shapes of the RRL MDFs are well described by pre-enrichment models. This suggests two possible channels for the early chemical evolution for these Sculptor group dTrans galaxies: (1) the ancient stellar populations of our target dwarf galaxies might have formed from the star forming gas which was already enriched through "prompt initial enrichment" or an "initial nucleosynthetic spike" from the very first massive stars, or (2) this pre-enrichment state might have been achieved by the end products from more evolved systems of their nearest neighbor, NGC 55. We also study the environmental effects of the formation and evolution of our target dTrans galaxies by comparing their properties with those of 79 volume limited (D_{sun}_<2Mpc) dwarf galaxy samples in terms of the luminosity-metallicity relation and the H I gas content. The presence of these RRL stars strongly supports the idea that although the Sculptor Group galaxies have a considerably different environment from the Local Group (e.g., no giant host galaxies, loosely bound and very low local density), they share a common epoch of early star formation with the dwarf satellite galaxies in the Local Group.2014ApJ...784...76Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/784/76CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/550/A7 : HST photometry of Sculptor dwarf galaxies (Lianou+, 2013)J/AJ/145/101 : Updated nearby galaxy catalog (Karachentsev+, 2013)J/MNRAS/425/1459 : RR Lyrae in M32 (Sarajedini+, 2012)J/AJ/141/171 : RR Lyrae in six ultra-deep fields of M31 (Jeffery+, 2011)J/AJ/139/357 : Variable stars in NGC 5286 (Zorotovic+, 2010)J/ApJ/724/799 : RR Lyrae variables in M33. II. (Yang+, 2010)J/AJ/132/1361 : RR Lyrae variables in M33 (Sarajedini+, 2006)J/AJ/129/267 : RR Lyrae variables in NGC 5272 (Cacciari+, 2005)J/AJ/127/2031 : Catalog of neighboring galaxies (Karachentsev+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/784/76https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/784/76http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/784/76https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/784/76https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/784/76http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/784/76GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/784/76/table4 (Pulsation properties of anomalous Cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/784/76/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/784/76/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/784/76/table4?GETtext/xml+votable180.050000true6.6338333-41.86373610.005555555555555556Cone search capability for table J/ApJ/784/76/table5 (Physical properties of nearby dwarf satellite galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/784/76/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/784/76/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/784/76/table5?GETtext/xml+votable180.050000true13.158333-72.8002780.005555555555555556Cone search capability for table J/ApJ/784/76/stars (Pulsation properties of RR Lyrae stars in ESO294-G010 , and in ESO410-G005)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/784/76/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/784/76/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/784/76/stars?GETtext/xml+votable180.050000true6.6144583-41.86525830.0055555555555555566/619 2110 2216 2234 2272 2297 2565 2572 2573 2604 2611 2622 2628 2668 2676 2709 2746 2755 2758 2767 2774 2777 2781 2789 2830 2852 3042 4410 4419 5287 5939 6021 7416 8745 10153 10183 10308 10444 10769 11691 13505 13655 14149 16459 17165 17229 18041 18926 19833 19990 20262 20416 20437 20440 26487 26858 26980 27000 27207 27351 27580 28136 28361 29699 29718 31692 33096 33317 35206 35482 35720 35969 38841 38846 39100 45423 46597 48035 489423.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/784/76?format=asciiInfraredOpticaldefaultJ/ApJ/784/76/table4Pulsation properties of anomalous CepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyGalaxy identifier (ESO294-G010 or ESO410-G005)meta.id.parentcharFieldHST/ACS field (WFC1 or WFC2) (G1)meta.id;instrcharStar[879/23638] Variable identifiermeta.id;meta.mainintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.main<Vmag>[24.2/26.6] Mean Johnson V band magnitude (VEGAmag system)magphot.mag;em.opt.Vfloat<V-I>[0.25/0.7] Mean Johnson (V-I) color index (VEGAmag system)magphot.color;em.opt.V;em.opt.IfloatPer[0.42/1.95] Perioddtime.periodfloatVamp[0.25/1.29] The V band amplitudemagsrc.var.amplitudefloatBl[bl] The flag "bl" indicates a blended objectmeta.codecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/784/76/table5Physical properties of nearby dwarf satellite galaxiesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupGalaxy group (MW, M31, Antilia, or Sculptor)src.class.starGalaxy;pos.lgcharNameName of the nearby dwarf satellite galaxy (1)meta.id;meta.maincharK13Source in Karachentsev et al. (cat. J/AJ/145/101) within 1.5''meta.ref.urlintnullableRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainDist[0.02/1.97]Distance from the Sun (D_{Sun}_)Mpcpos.distance;pos.heliocentricfloatBMag[-17.9/-0.7]? Absolute B band magnitudemagphys.magAbs;em.opt.Bfloatnullable<[Fe/H]>[-2.7/-0.5]? Mean metallicitylog(Sun)phys.abund.Fefloatnullablee_<[Fe/H]>[0.03/0.8]? Uncertainty in <[Fe/H]>log(Sun)stat.error;phys.abund.Fefloatnullabler_<[Fe/H]>Reference for <[Fe/H]> (2)meta.refcharlogMHI[1.12/8.66]? Log of HI masslog(solMass)phys.massfloatnullablelogLK[3.24/9.42]? Log of K-band luminositylog(solLum)phys.luminosity;em.IR.KfloatnullableTi5[-0.7/5.3] The tidal index ({Theta}_5_) (3)src.class.structfloatMTypeGalaxy morphological type (BCD, dE, dIrr, dSph, dTran, or uFd) (4)src.morph.typecharJ/ApJ/784/76/starsPulsation properties of RR Lyrae stars in ESO294-G010 , and in ESO410-G005Per[0.2/0.83] Perioddtime.periodfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyGalaxy name (ESO294-G010 or ESO410-G005)meta.id.parentcharTypeRR Lyrae type (RRab or RRc)meta.code;src.varcharFieldHST/ACS field (WFC1 or WFC2) (G1)meta.id;instrcharStar[14904/36753] Variable identifiermeta.id;meta.mainintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.main<Vmag>[26.6/27.3] Mean Johnson V band magnitude (VEGAmag system)magphot.mag;em.opt.Vfloat<V-I>[0.17/0.73] Mean Johnson (V-I) color index (VEGAmag system)magphot.color;em.opt.V;em.opt.IfloatVamp[0.32/1.5] V band amplitudemagsrc.var.amplitudefloatBl[bl] The flag "bl" indicates a blended objectmeta.codecharSimbadSimbad column added by the CDSmeta.ref.urlchar