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

Horta, Danny ; Schiavon, Ricardo P. ; Mackereth, J. Ted ; Weinberg, David H. ; Hasselquist, Sten ; Feuillet, Diane LU orcid ; O’Connell, Robert W. ; Anguiano, Borja ; Allende-Prieto, Carlos and Beaton, Rachael L. , et al. (2023) In Monthly Notices of the Royal Astronomical Society 520(4). p.5671-5711
Abstract

Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalized dwarf galaxies. The chemodynamical 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... (More)

Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalized dwarf galaxies. The chemodynamical 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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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
dynamics, Galaxy: abundances, Galaxy: evolution, Galaxy: formation, Galaxy: general, Galaxy: halo, Galaxy: kinematics
in
Monthly Notices of the Royal Astronomical Society
volume
520
issue
4
pages
41 pages
publisher
Oxford University Press
external identifiers
  • scopus:85159283515
ISSN
0035-8711
DOI
10.1093/mnras/stac3179
language
English
LU publication?
yes
id
2584a280-4625-41ae-965c-59814a509fda
date added to LUP
2023-08-11 13:33:03
date last changed
2024-04-20 01:25:10
@article{2584a280-4625-41ae-965c-59814a509fda,
  abstract     = {{<p>Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalized dwarf galaxies. The chemodynamical 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.</p>}},
  author       = {{Horta, Danny and Schiavon, Ricardo P. and Mackereth, J. Ted and Weinberg, David H. and Hasselquist, Sten and Feuillet, Diane and O’Connell, Robert W. and Anguiano, Borja and Allende-Prieto, Carlos and Beaton, Rachael L. and Bizyaev, Dmitry and Cunha, Katia and Geisler, Doug and García-Hernández, D. A. and Holtzman, Jon and Jönsson, Henrik and Lane, Richard R. and Majewski, Steve R. and Mészáros, Szabolcs and Minniti, Dante and Nitschelm, Christian and Shetrone, Matthew and Smith, Verne V. and Zasowski, Gail}},
  issn         = {{0035-8711}},
  keywords     = {{dynamics; Galaxy: abundances; Galaxy: evolution; Galaxy: formation; Galaxy: general; Galaxy: halo; Galaxy: kinematics}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{4}},
  pages        = {{5671--5711}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{The chemical characterization of halo substructure in the Milky Way based on APOGEE}},
  url          = {{http://dx.doi.org/10.1093/mnras/stac3179}},
  doi          = {{10.1093/mnras/stac3179}},
  volume       = {{520}},
  year         = {{2023}},
}