J/A+A/691/A333ivo://CDS.VizieR/J/A+A/691/A333doi:10.26093/cds/vizier.36910333CDSErnandes H.Feuillet D.Feltzing S.Skuladottir A.2025-02-27T20:02:14Z2024-11-25T09:11:33ZCDS support team

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

cds-question@unistra.frmilky-way-galaxystellar-ageschemical-abundanceseffective-temperatureThe Gaia-Sausage-Enceladus merger was a major event in the history of the Milky Way. Debris from this merger has been extensively studied with full kinematic data from the Gaia mission. Understanding the star formation history of the progenitor galaxy aids in our understanding of the evolution of the Milky Way and galaxy formation in general. We aimed to constrain the star formation history of the Gaia-Sausage-Enceladus progenitor galaxy using elemental abundances of member stars. Previous studies on Milky Way satellite dwarf galaxies show that key elemental abundance patterns, which probe different nucleosynthetic channels, reflect the host galaxy's star formation history. We gathered Mg, Fe, Ba, and Eu abundance measurements for Gaia-Sausage-Enceladus stars from the SAGA database. Gaia-Sausage-Enceladus members were selected kinematically. Inspired by previous studies, we used [Fe/Mg], [Ba/Mg], [Eu/Mg], and [Eu/Ba], as a function of [Fe/H] to constrain the star formation history of Gaia-Sausage-Enceladus. We used the known star formation histories and elemental abundance patterns of the Sculptor and Fornax dwarf spheroidal galaxies as a comparison. Results. The elemental abundance ratios of [Fe/Mg], [Ba/Mg], [Eu/Mg], and [Eu/Ba] all increase with [Fe/H] in Gaia-Sausage- Enceladus. The [Eu/Mg] begins to increase at [Fe/H]~-2.0 and continues steadily, contrasting with the trend observed in the Sculptor dSph galaxy. The [Eu/Ba] increases and remains high across the [Fe/H] range, unlike the pattern seen in the Sculptor dSph galaxy, and deviates from the Fornax dSph galaxy at high [Fe/H]. The [Ba/Mg] is higher than those of the Sculptor dSph galaxy at the lowest [Fe/H] and gradually increases, similar to the Fornax dSph galaxy. We constrained three main properties of the Gaia-Sausage-Enceladus star formation history: (1) star formation started gradually, (2) it extended for over 2 Gyr, and (3) it was quenched around [Fe/H] of ~0.5, likely when it fell into the Milky Way. We show that the elemental abundance ratios [Fe/Mg], [Ba/Mg], [Eu/Mg], and [Eu/Ba] can be used to trace the star formation history of a disrupted galaxy when these measurements are available over an [Fe/H] range that is representative of the progenitor galaxy's stellar population.2024A&A...691A.333Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/691/A333CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/691/A333https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/691/A333http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/691/A333https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/691/A333https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/691/A333http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/691/A333GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/691/A333/table1 (Gaia and SAGA IDs, median SAGA stellar parameters, elemental abundances, photometric Teff (only for dwarf stars), median age with 16 and 84 percentile, and r-II flag for stars selected according to the Feuillet et al. (2021MNRAS.508.1489F) scheme)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/691/A333/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/691/A333/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/691/A333/table1?GETtext/xml+votable180.050000true290.0862481-66.45564080.0055555555555555566/1911 4376 4901 5341 5622 6256 7117 8474 10165 10359 12621 13132 13829 14576 14762 14931 15124 15158 16582 17398 17412 17811 18483 18553 18561 19342 20643 21195 21233 22205 23107 23428 23892 23978 24752 24942 25767 25835 26012 26191 26260 27148 27162 28459 28475 29703 30528 30952 31592 33286 33753 34260 34589 36465 36474 36587 36755 37055 38986 39157 39208 39446 42100 43360 43932 43957 44245 45717 46098 46909 47092 47698 48946https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/691/A333?format=asciidefaultJ/A+A/691/A333/table1Gaia and SAGA IDs, median SAGA stellar parameters, elemental abundances, photometric Teff (only for dwarf stars), median age with 16 and 84 percentile, and r-II flag for stars selected according to the Feuillet et al. (2021MNRAS.508.1489F) schemerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 IDmeta.idNameSimbad ID used in SAGAmeta.id;meta.maincharTeffMedian effective temperature from SAGA databaseKphys.temperature.effective;stat.medianfloatloggMedian surface gravity from SAGA databaselog(cm.s**-2)phys.gravity;stat.medianfloat[Fe/H]Median [Fe/H] from SAGA databasephys.abund.Fe;stat.medianfloat[Mg/Fe]? Median [Mg/Fe] from SAGA databasephys.abundfloatnullable[Ba/Fe]? Median [Ba/Fe] from SAGA databasephys.abundfloatnullable[Eu/Fe]Median [Eu/Fe] from SAGA databasephys.abundfloatTeffph? Photometric effective temperatureKphys.temperature.effectivedoublenullableAge? Median ageGyrtime.age;stat.medianfloatnullableE_Age? 84th percentile in AgeGyrstat.error;stat.maxfloatnullabler-II[false true] r-II star flagmeta.codecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.maine_Age? 16th percentile in AgeGyrstat.error;time.agefloatnullable