J/A+A/572/A10ivo://CDS.VizieR/J/A+A/572/A10doi:10.26093/cds/vizier.35720010CDSde Boer T.J.L.Tolstoy E.Lemasle B.Saha A.Olszewski E.W.Mateo M.,Irwin M.J.Battaglia G.2015-04-05T15:17:57Z2014-11-18T08:21:43ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryvisible-astronomybroad-band-photometryWe present deep photometry of the Carina dwarf Spheroidal galaxy in the B,V filters from CTIO/MOSAIC, out to and beyond the tidal radius of r_ell_~0.48{deg}. The accurately calibrated photometry is combined with spectroscopic metallicity distributions of Red Giant Branch stars to determine the detailed star formation and chemical evolution history of Carina. The star formation history confirms the episodic formation history of Carina and quantifies the duration and strength of each episode in great detail, as a function radius from the centre. Two main episodes of star formation occurred at old (>8Gyr) and intermediate (2-8Gyr) ages, both enriching stars starting from low metallicities ([Fe/H]<-2dex). By dividing the SFH into two components, we determine that 60+/-9 percent of the total number of stars formed within the intermediate age episode. Furthermore, within the tidal radius (0.48{deg} or 888pc) a total mass in stars of 1.07+/-0.08x10^6^M_{sun}_ was formed, giving Carina a stellar mass-to-light ratio of 1.8+/-0.8. Combining the detailed star formation history with spectroscopic observations of RGB stars, we are able to determine the detailed age-metallicity relation of each episode and the timescale of alpha-element evolution of Carina from individual stars. The oldest episode displays a tight age-metallicity relation during ~6Gyr with steadily declining alpha-element abundances and a possible alpha-element knee visible at [Fe/H]~-2.5dex. The intermediate age sequence displays a more complex age-metallicity relation starting from low metallicity and a sequence in alpha-element abundances with a slope much steeper than observed in the old episode, starting from [Fe/H]=-1.8dex and [Mg/Fe]~0.4dex and declining to Mg-poor values ([Mg/Fe]<-0.5dex). This indicates clearly that both episodes of star formation formed from gas with different abundance patterns , inconsistent with simple evolution in an isolated system.2014A&A...572A..10Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/572/A10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/115/1840 : BV photometry in Carina dwarf galaxy (Hurley-Keller+ 1998)J/A+A/410/523 : Carina Spiral Feature ubvybeta photometry (Kaltcheva, 2003)J/A+A/514/A59 : uvby{beta} photometry in Carina. II (Kaltcheva+, 2010)J/ApJ/667/963 : Near-infrared photometry of Carina nebula (Sanchawala+, 2007)J/ApJ/649/201 : Carina dSph velocities and Washington photometry (Munoz+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/572/A10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/572/A10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/572/A10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/572/A10https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/572/A10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/572/A10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/572/A10/table1 (BV photometry for all our targets in Carina dSph)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/572/A10/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/572/A10/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/572/A10/table1?GETtext/xml+votable180.050000true99.56786361-50.956146110.0055555555555555565/9774 6/39091 39094-39095 39100-391013.322582951404819e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/572/A10?format=asciiOpticaldefaultJ/A+A/572/A10/table1BV photometry for all our targets in Carina dSphrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)degpos.eq.dec;meta.mainindexedRell[0/1.7] Ellipitcal radius from centre of Carinadegphys.angSizefloatVmag[12.8/25.8] V magnitudemagphot.mag;em.opt.Vfloatq_Vmag[1/3] Quality flag for V magnitude, 1=ok (1)meta.code.qualinte_VmagError on V magnitudemagstat.error;phot.mag;em.opt.VfloatBmag[13.3/26.5] B magnitudemagphot.mag;em.opt.Bfloatq_Bmag[1/3] Quality flag for B magnitude, 1=ok (1)meta.code.qualinte_BmagError on B magnitudemagstat.error;phot.mag;em.opt.BfloatJ/A+A/572/A10/table2Star formation rates as a function of agerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAgeMean age of star formation history (SFH) binGyrphys.SFR;stat.meanfloate_AgeBinsize of SFH age binGyrstat.error;time.agefloatSFR1Star formation rate using DSEP isochrones in first annulus (0<rad<0.15deg)solMass/Myrphys.SFRfloate_SFR1Error on SFR1solMass/Myrstat.errorfloatSFR2Star formation rate using DSEP isochrones in second annulus (0.15<rad<0.30deg)solMass/Myrphys.SFRfloate_SFR2Error on SFR2solMass/Myrstat.errorfloatSFR3Star formation rate using DSEP isochrones in third annulus (0.30<rad<0.48deg)solMass/Myrphys.SFRfloate_SFR3Error on SFR3solMass/Myrstat.errorfloatSFRBaS1Star formation rate using BaSTI isochrones in first annulus (0<rad<0.15deg)solMass/Myrphys.SFRfloate_SFRBaS1Error on SFRBaS1solMass/Myrstat.errorfloatSFRBaS2Star formation rate using BaSTI isochrones in second annulus (0.15<rad<0.30deg)solMass/Myrphys.SFRfloate_SFRBaS2Error on SFRBaS2solMass/Myrstat.errorfloatSFRBaS3Star formation rate using BaSTI isochrones in third annulus (0.30<rad<0.48deg)solMass/Myrphys.SFRfloate_SFRBaS3Error on SFRBaS3solMass/Myrstat.errorfloatJ/A+A/572/A10/table3Star formation rates as a function of metallicitye_SFR3Error on SFR3solMassstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[Fe/H]Mean [Fe/H] of star formation history (SFH) binlog(Sun)phys.SFR;stat.meanfloate_[Fe/H]Binsize of Star Formation History bin in dexlog(Sun)stat.error;phys.abund.FefloatSFR1Star formation rate (Msun/dex) using DSEP isochrones in first annulus (0<rad<0.15deg)solMassphys.SFRfloate_SFR1Error on SFR1solMassstat.errorfloatSFR2Star formation rate (Msun/dex) using DSEP isochrones in second annulus (0.15<rad<0.30deg)solMassphys.SFRfloate_SFR2Error on SFR2solMassstat.errorfloatSFR3Star formation rate (Msun/dex) using DSEP isochrones in third annulus (0.30<rad<0.48deg)solMassphys.SFRfloatSFRB1Star formation rate (Msun/dex) using BaSTI isochrones in first annulus (0<rad<0.15deg)solMassphys.SFRfloate_SFRB1Error on SFRB1solMassstat.errorfloatSFRB2Star formation rate (Msun/dex) using BaSTI isochrones in second annulus (0.15<rad<0.30deg)solMassphys.SFRfloate_SFRB2Error on SFRB2solMassstat.errorfloatSFRB3Star formation rate (Msun/dex) using BaSTI isochrones in third annulus (0.30<rad<0.48deg)solMassphys.SFRfloate_SFRB3Error on SFRB3solMassstat.errorfloat