Autor(es)

Limberg, Guilherme ; Souza, Stefano O. ; Perez-Villegas, Angeles ; Rossi, Silvia ; Perottoni, Helio D. ; Santucci, Rafael M.

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 935, n. 2, p. 16-pg., 2022-08-01.

Resumo

We combine spectroscopic, photometric, and astrometric information from APOGEE data release 17 and Gaia early data release 3 to perform a self-consistent characterization of Gaia-Sausage/Enceladus (GSE), the remnant of the last major merger experienced by the Milky Way, considering stars and globular clusters (GCs) altogether. Our novel set of chemodynamical criteria to select genuine stars of GSE yields a metallicity distribution function with a median [Fe/H] of -1.22 and 0.23 dex dispersion. Stars from GSE present an excess of [Al/Fe] and [Mg/Mn] (also [Mg/Fe]) in comparison to surviving Milky Way dwarf satellites, which can be explained by differences in star formation efficiencies and timescales between these systems. However, stars from Sequoia, another proposed accreted halo substructure, essentially overlap the GSE footprint in all analyzed chemical-abundance spaces, but present lower metallicities. Among the probable GCs of GSE with APOGEE observations available, we find no evidence for atypical [Fe/H] spreads with the exception of omega Centauri (omega Cen). Under the assumption that omega Cen is a stripped nuclear star cluster, we estimate the stellar mass of its progenitor to be M-star approximate to 1.3 x 10(9) M-circle dot, well within literature expectations for GSE. This leads us to envision GSE as the best available candidate for the original host galaxy of omega Cen. We also take advantage of Gaia's photometry and APOGEE metallicities as priors to determine fundamental parameters for eight high-probability (>70%) GC members of GSE via statistical isochrone fitting. Finally, the newly determined ages and APOGEE [Fe/H] values are utilized to model the age-metallicity relation of GSE. (AU)

• Processo FAPESP: 15/50374-0 - Mosaic: the multi-object spectrograph for the ESO Extremely Large Telescope
• Beneficiário: Silvia Cristina Fernandes Rossi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/18100-4 - Populações estelares na Via Láctea: bojo, halo, disco e regiões de formação de estrelas; instrumentação para espectroscopia de alta resolução
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 18/22044-3 - Aglomerados globulares do bojo: relíquias da formação e evolução da galáxia
• Beneficiário: Stefano Oliveira de Souza
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 21/10429-0 - A estrutura quimiodinâmica do halo galáctico
• Beneficiário: Guilherme Limberg
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto