Extending the chemical reach of the H3 survey: detailed abundances of the dwarf-galaxy stellar stream Wukong/LMS-1

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Limberg, Guilherme ; Ji, Alexander P. ; Naidu, Rohan P. ; Chiti, Anirudh ; Rossi, Silvia ; Usman, Sam A. ; Ting, Yuan-Sen ; Zaritsky, Dennis ; Bonaca, Ana ; Borbolato, Lais ; Speagler, Joshua S. ; Chandra, Vedant ; Conroy, Charlie

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 530, n. 3, p. 14-pg., 2024-04-25.

Resumo

We present the first detailed chemical-abundance analysis of stars from the dwarf-galaxy stellar stream Wukong/LMS-1 covering a wide metallicity range (-3.5 < [Fe/H] less than or similar to -1.3). We find abundance patterns that are effectively indistinguishable from the bulk of Indus and Jhelum, a pair of smaller stellar streams proposed to be dynamically associated with Wukong/LMS-1. We confirmed a carbon-enhanced metal-poor star ([C/Fe] > +0.7 and [Fe/H] similar to -2.9) in Wukong/LMS-1 with strong enhancements in Sr, Y, and Zr, which is peculiar given its solar-level [Ba/Fe]. Wukong/LMS-1 stars have high abundances of alpha elements up to [Fe/H] greater than or similar to -2$, which is expected for relatively massive dwarfs. Towards the high-metallicity end, Wukong/LMS-1 becomes alpha-poor, revealing that it probably experienced fairly standard chemical evolution. We identified a pair of N- and Na-rich stars in Wukong/LMS-1, reminiscent of multiple stellar populations in globular clusters. This indicates that this dwarf galaxy contained at least one globular cluster that was completely disrupted in addition to two intact ones previously known to be associated with Wukong/LMS-1, which is possibly connected to similar evidence found in Indus. From these >= 3 globular clusters, we estimate the total mass of Wukong/LMS-1 to be approximate to 10(10)M(circle dot), representing similar to 1 per cent of the present-day Milky Way. Finally, the [Eu/Mg] ratio in Wukong/LMS-1 continuously increases with metallicity, making this the first example of a dwarf galaxy where the production of r-process elements is clearly dominated by delayed sources, presumably neutron-star mergers. (AU)

• Processo FAPESP: 22/07301-5 - Perfis de abundâncias químicas de galáxias anãs destruídas
• Beneficiário: Guilherme Limberg
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
• Processo FAPESP: 21/10429-0 - A estrutura quimiodinâmica do halo galáctico
• Beneficiário: Guilherme Limberg
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• 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: 20/15245-2 - Espectrógrafo multi-objeto (MOSAIC) para o extremely large telescope: espectroscopia de populações estelares na via láctea e em galáxias
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais