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Profile picture Diane Feuillet

Diane Feuillet

Researcher

Profile picture Diane Feuillet

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

Author

  • Danny Horta
  • Ricardo P. Schiavon
  • J. Ted Mackereth
  • David H. Weinberg
  • Sten Hasselquist
  • Diane Feuillet
  • Robert W. O’Connell
  • Borja Anguiano
  • Carlos Allende-Prieto
  • Rachael L. Beaton
  • Dmitry Bizyaev
  • Katia Cunha
  • Doug Geisler
  • D. A. García-Hernández
  • Jon Holtzman
  • Henrik Jönsson
  • Richard R. Lane
  • Steve R. Majewski
  • Szabolcs Mészáros
  • Dante Minniti
  • Christian Nitschelm
  • Matthew Shetrone
  • Verne V. Smith
  • Gail Zasowski
Show all

Summary, in English

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.

Department/s

  • Department of Geology
  • eSSENCE: The e-Science Collaboration
  • Lund Observatory - Has been reorganised

Publishing year

2023-04-01

Language

English

Pages

5671-5711

Publication/Series

Monthly Notices of the Royal Astronomical Society

Volume

520

Issue

4

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • dynamics
  • Galaxy: abundances
  • Galaxy: evolution
  • Galaxy: formation
  • Galaxy: general
  • Galaxy: halo
  • Galaxy: kinematics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0035-8711