The detailed chemical abundance patterns of accreted halo stars from the optical to infrared

Carrillo, Andreia; Hawkins, Keith; Jofré, Paula; Silva, Danielle de Brito; Das, Payel; Lucey, Madeline

doi:10.48550/arxiv.2202.10416

Cited by 2 publications

(4 citation statements)

References 120 publications

(273 reference statements)

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“…Since its discovery (Belokurov et al 2018;Helmi et al 2018), the Gaia-Enceladus/Sausage (GES) substructure has been extensively studied, both from an orbital and chemical compositions perspective (e.g., Hayes et al 2018;Mackereth et al 2019;Koppelman et al 2019a;Vincenzo et al 2019;Aguado et al 2021b;Feuillet et al 2020;Monty et al 2020;Simpson et al 2020;An & Beers 2021;Horta et al 2021;Hasselquist et al 2021;Buder et al 2022;Carrillo et al 2022). In this work, we have identified a large sample of GES stars, and have shown that stars belonging to this population are characterized by intermediate-to-high orbital energies and high eccentricity, displaying no significant systemic disc-like rotation.…”

Section: Gaia-enceladus/sausagementioning

confidence: 90%

“…Sagittarius dSph, Ibata et al 1994;Helmi stream, Helmi et al 1999), the identification of accretion events early in the life of the Milky Way has proven difficult due to phase-mixing. A possible solution to this conundrum resides in the use of additional information, typically in the form of detailed chemistry and/or ages (e.g., Nissen & Schuster 2010;Hawkins et al 2015;Hayes et al 2018;Haywood et al 2018;Mackereth et al 2019;Das et al 2020;Montalbán et al 2020;Horta et al 2021;Hasselquist et al 2021;Buder et al 2022;Carrillo et al 2022).…”

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confidence: 99%

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The chemical characterization of halo substructure in the Milky Way based on APOGEE

Horta

Schiavon²,

Mackereth

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalised dwarf galaxies. The chemo-dynamical information recorded in their stellar populations helps elucidate their nature, constraining the assembly history of the Galaxy. Using data from APOGEE and Gaia, we examine the chemical properties of various halo substructures, considering elements that sample various nucleosynthetic pathways. The systems studied are Heracles, Gaia-Enceladus/Sausage (GES), the Helmi stream, Sequoia, Thamnos, Aleph, LMS-1, Arjuna, I’itoi, Nyx, Icarus, and Pontus. Abundance patterns of all substructures are cross-compared in a statistically robust fashion. Our main findings include: (i) the chemical properties of most substructures studied match qualitatively those of dwarf Milky Way satellites, such as the Sagittarius dSph. Exceptions are Nyx and Aleph, which are chemically similar to disc stars, implying that these substructures were likely formed in situ; (ii) Heracles differs chemically from in situ populations such as Aurora and its inner halo counterparts in a statistically significant way. The differences suggest that the star formation rate was lower in Heracles than in the early Milky Way; (iii) the chemistry of Arjuna, LMS-1, and I’itoi is indistinguishable from that of GES, suggesting a possible common origin; (iv) all three Sequoia samples studied are qualitatively similar. However, only two of those samples present chemistry that is consistent with GES in a statistically significant fashion; (v) the abundance patterns of the Helmi stream and Thamnos are different from all other halo substructures.

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Section: Gaia-enceladus/sausagementioning

confidence: 90%

mentioning

confidence: 99%

The chemical characterization of halo substructure in the Milky Way based on APOGEE

Horta

Schiavon²,

Mackereth

et al. 2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Since its discovery (Belokurov et al 2018;Helmi et al 2018), the Gaia-Enceladus/Sausage (GES) substructure has been extensively studied, both from an orbital and chemical compositions perspective (e.g., Hayes et al 2018;Mackereth et al 2019;Koppelman et al 2019a;Vincenzo et al 2019;Aguado et al 2020;Feuillet et al 2020;Simpson et al 2020;An & Beers 2021;Horta et al 2021a;Hasselquist et al 2021;Buder et al 2022;Carrillo et al 2022). In this work, we have identified a large sample of GES stars, and have shown that stars belonging to this population are characterized by intermediate-tohigh orbital energies and high eccentricity, displaying no significant systemic disc-like rotation.…”

Section: Gaia-enceladus/sausagementioning

confidence: 99%

“…Sagittarius dSph, Ibata et al 1994;Helmi stream, Helmi et al 1999), the identification of accretion events early in the life of the Milky Way has proven difficult due to phase-mixing. A possible solution to this conundrum resides in the use of additional information, typically in the form of detailed chemistry and/or ages (e.g., Nissen & Schuster 2010;Hawkins et al 2015;Hayes et al 2018;Haywood et al 2018;Mackereth et al 2019;Das et al 2020;Montalbán et al 2020;Horta et al 2021a;Hasselquist et al 2021;Buder et al 2022;Carrillo et al 2022).…”

Section: Introductionmentioning

confidence: 99%

The chemical characterisation of halo substructure in the Milky Way based on APOGEE

Horta¹,

Schiavon²,

Mackereth³

et al. 2022

Preprint

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Galactic haloes in a Λ-Cold Dark Matter (ΛCDM) universe are predicted to host today a swarm of debris resulting from cannibalised dwarf galaxies that have been accreted via the process of hierarchical mass assembly. The chemo-dynamical information recorded in the Galactic stellar populations associated with such systems helps elucidate their nature, placing constraints on the mass assembly history of the Milky Way. Using data from the APOGEE and Gaia surveys, we examine APOGEE targets belonging to the following substructures in the stellar halo: Heracles, Gaia-Enceladus/Sausage (GES), Sagittarius dSph, the Helmi stream, Sequoia, Thamnos, Aleph, LMS-1, Arjuna, I'itoi, Nyx, Icarus, and Pontus. We examine the distributions of all substructures in chemical space, considering the abundances of elements sampling various nucleosynthetic pathways. Our main findings include: i) the chemical properties of GES, Heracles, the Helmi stream, Sequoia, Thamnos, LMS-1, Arjuna, and I'itoi match qualitatively those of dwarf satellites of the Milky Way, such as the Sagittarius dSph; ii) the abundance pattern of the recently discovered inner Galaxy substructure Heracles differs statistically from that of populations formed in situ. Heracles also differs chemically from all other substructures; iii) the abundance patterns of Sequoia (selected in various ways), Arjuna, LMS-1, and I'itoi are indistinguishable from that of GES, indicating a possible common origin; iv) the abundance patterns of the Helmi stream and Thamnos substructures are different from all other halo substructures; v) the chemical properties of Nyx and Aleph are very similar to those of disc stars, implying that these substructures likely have an in situ origin.

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The detailed chemical abundance patterns of accreted halo stars from the optical to infrared

Cited by 2 publications

References 120 publications

The chemical characterization of halo substructure in the Milky Way based on APOGEE

The chemical characterization of halo substructure in the Milky Way based on APOGEE

The chemical characterisation of halo substructure in the Milky Way based on APOGEE

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