J/MNRAS/489/5900ivo://CDS.VizieR/J/MNRAS/489/5900doi:10.26093/cds/vizier.74895900CDSDa Costa G.S.Bessell M.S.Mackey A.D.Nordlander T.Asplund M.,Casey A.R.Frebel A.Lind K.Marino A.F.Murphy S.J.Norris J.E.,Schmidt B.P.Yong D.2024-08-20T20:13:22Z2023-02-14T15:01:22ZCDS support team

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

cds-question@unistra.frmetallicitychemically-peculiar-starspopulation-ii-starsmilky-way-galaxyinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present and discuss the results of a search for extremely metal-poor stars based on photometry from data release DR1.1 of the SkyMapper imaging survey of the southern sky. In particular, we outline our photometric selection procedures and describe the low-resolution (R~3000) spectroscopic follow-up observations that are used to provide estimates of effective temperature, surface gravity, and metallicity ([Fe/H]) for the candidates. The selection process is very efficient: of the 2618 candidates with low-resolution spectra that have photometric metallicity estimates less than or equal to -2.0, 41 per cent have [Fe/H]=<-2.75 and only approximately seven per cent have [Fe/H]>-2.0dex. The most metal-poor candidate in the sample has [Fe/H]<-4.75 and is notably carbon rich. Except at the lowest metallicities ([Fe/H]<-4), the stars observed spectroscopically are dominated by a 'carbon-normal' population with [C/Fe]_1D,LTE_=<+1dex. Consideration of the A(C)_1D,LTE_ versus [Fe/H]_1D,LTE_ diagram suggests that the current selection process is strongly biased against stars with A(C)_1D,LTE_>7.3 (predominantly CEMP-s) while any bias against stars with A(C)_1D,LTE_<7.3 and [C/Fe]_1D,LTE_>+1 (predominantly CEMP-no) is not readily quantifiable given the uncertainty in the SkyMapper v-band DR1.1 photometry. We find that the metallicity distribution function of the observed sample has a power-law slope of {Delta}(LogN)/{Delta}[Fe/H]=1.5+/-0.1dex per dex for -4.0=<[Fe/H]=<-2.75, but appears to drop abruptly at [Fe/H]~-4.2, in line with previous studies.2019MNRAS.489.5900Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/489/5900CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/489/5900https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/489/5900http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/489/5900https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/489/5900https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/489/5900http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/489/5900GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/489/5900/table1 (Comparison of [Fe/H]_fitter_ values with those from high-dispersion spectroscopy literature values)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/5900/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/5900/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/5900/table1?GETtext/xml+votable180.050000true181.172451912.0198650.005555555555555556Cone search capability for table J/MNRAS/489/5900/table2 (Details of the derived parameters for the observed stars with [Fe/H]_fitter_<-3.0)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/5900/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/5900/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/5900/table2?GETtext/xml+votable180.050000true241.4174167-14.72308330.005555555555555556Cone search capability for table J/MNRAS/489/5900/table3 (Details of the derived parameters for additional candidates with [Fe/H]_fitter_<-3.0)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/489/5900/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/489/5900/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/489/5900/table3?GETtext/xml+votable180.050000true131.2382083-26.72369440.0055555555555555566/17040 17095 17353 17385 17543 18056 18640 18692 18850 18945 20496 20671 21773-21774 22534 24681 24696 24703 24780 24846 24903 25019 25530 25761 26205 26265 26673 26775 26795 26927 26990 27001 27170 27235 27846 29776 29778 29795 30016 30872 31233 32797 32809 32855 32966 32980 33012 33058 33185 33412 33464 33560 33641-33642 33771 33999 34023 34077 34491 34684 34943 35022 35117 35414 35532 35813 36033 36193 36705 37078 37086 37089 37289-37290 37537 37581 37583 37645 38122 38138 38173 38182 38275 38355 38431 38485 38487-38488 38519 38755 38766 38794 40056 40119 40144 40153 40162 40167 40299-40300 40333 40445 40572 40709 40723 40747 40963 40987 41038 41073 41109 41253 41260 41281 41315-41316 41324 42011 42020-42021 42034 42037 42086 42097 42113 42331 42943 43293 43310 43370 43619 43625 43699 43741 43991 44040 44060 44079 44082 44088 44117 44238 44249 44406 44416 44478 44501 44562 44627 44890 44990 45271 45365 45502 45608 45655 45843-45844 45850 45913 46023 46068 46157 46242 46339 46606 46739 46759 46845 46871 47075 47125 47135 47231 47330 47332 47469 47664 47715 47729 47745 47849 47897 47915 48006-48007 48093 48147 48238 48481 48488 48580 48631 48784 48807 49013 49097https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/489/5900?format=asciiOpticalInfrareddefaultJ/MNRAS/489/5900/table1Comparison of [Fe/H]_fitter_ values with those from high-dispersion spectroscopy literature valuesSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.mainchar[Fe/H]hdFe/H abundance ratio from high-dispersion spectroscopy from literaturephys.abund.Fefloat[Fe/H]fFe/H abundance ratio from the spectrophotometric fits to the 2.3m low-resolution WiFeS spectroscopyphys.abund.Fefloatr_[Fe/H]hdReferences for [Fe/H]hdmeta.refcharf_NameFlag on Name (1)meta.codechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/MNRAS/489/5900/table2Details of the derived parameters for the observed stars with [Fe/H]_fitter_<-3.0[Fe/H]fFe/H abundance ratio from the spectrophotometric fits to the 2.3m low-resolution WiFeS spectroscopyphys.abund.FefloatONameAlternative namemeta.idcharSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (SMSS JHHMMSS.ss-DDMMSS.s)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.maingmagSkyMapper DR1.1 g-band magnitudemagphot.mag;em.opt.Bfloatg-iSkyMapper DR1.1 (g-i)_0_ colour indexmagphot.color;em.opt;em.optfloatmiMetallicity index (G1)magphot.color;arith.difffloatEW(G)G-band equivalent width0.1nmspect.line.eqWidthfloatTeffEffective temperature from FITTERKphys.temperature.effectiveintloggSurface gravity from FITTERlog(cm.s**-2)phys.gravityfloatf_NameFlag on Name (1)meta.codecharJ/MNRAS/489/5900/table3Details of the derived parameters for additional candidates with [Fe/H]_fitter_<-3.0f_NameFlag on Name (1)meta.codeintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (SMSS JHHMMSS.ss-DDMMSS.s)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.maingmagSkyMapper DR1.1 g-band magnitudemagphot.mag;em.opt.Bfloatg-iSkyMapper DR1.1 (g-i)_0_ colour indexmagphot.color;em.opt;em.optfloatmiMetallicity index (G1)magphot.color;arith.difffloatEW(G)G-band equivalent width0.1nmspect.line.eqWidthfloatTeffEffective temperature from FITTERKphys.temperature.effectiveintloggSurface gravity from FITTERlog(cm.s**-2)phys.gravityfloat[Fe/H]fFe/H abundance ratio from the spectrophotometric fits to the 2.3m low-resolution WiFeS spectroscopyphys.abund.FefloatSimbadSimbad column added by the CDSmeta.ref.urlchar