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Peer-reviewedCC BYProceedings of the International Astronomical Union. International Astronomical Union

Tracing the accretion history of the Milky Way with halo stars

  • Alice Mori1,2
  • Paola Di Matteo3
  • Stefania Salvadori1,2
  1. 1Dipartimento di Fisica e Astronomia, Università di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
  2. 2INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
  3. 3LIRA, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, 92195 Meudon, France
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Abstract

The ΛCDM model predicts a hierarchical formation for galaxies. Many substructures were found in the Galactic halo, identified as clumps in kinematic spaces. If they also feature different chemical properties, they are then associated to independent merger debris. Our aim is to explore to what extent different clumps in the energy-angular momentum space ( E−L z ) with different metallicity distribution functions (MDF) trace the accretion history of the Galaxy. By means of N-body simulations, we confirm that accreted stars from a massive merger redistribute in a wide range of E and L z , due to dynamical friction, thus not being associated to a single clump. Since satellite stars with different metallicities can be deposited in different regions of the E−L z space, a single accretion can manifest with different MDFs. This method can bias the merger tree of the Galaxy towards increasing the number of accretions and decreasing the masses of the progenitor galaxies.

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Cite

BibTeXRIS
BibTeX
@article{mori2026tracing,
  title = {{Tracing the accretion history of the Milky Way with halo stars}},
  author = {Alice Mori and Paola Di Matteo and Stefania Salvadori},
  journal = {Proceedings of the International Astronomical Union. International Astronomical Union},
  year = {2026},
  month = aug,
  doi = {10.1017/s1743921325001000},
  url = {https://doi.org/10.1017/s1743921325001000},
  note = {CC BY},
}
RIS
TY  - JOUR
TI  - Tracing the accretion history of the Milky Way with halo stars
AU  - Alice Mori
AU  - Paola Di Matteo
AU  - Stefania Salvadori
PY  - 2026
DA  - 2026/08/11
JO  - Proceedings of the International Astronomical Union. International Astronomical Union
DO  - 10.1017/s1743921325001000
UR  - https://doi.org/10.1017/s1743921325001000
AB  - The ΛCDM model predicts a hierarchical formation for galaxies. Many substructures were found in the Galactic halo, identified as clumps in kinematic spaces. If they also feature different chemical properties, they are then associated to independent merger debris. Our aim is to explore to what extent different clumps in the energy-angular momentum space ( E−L z ) with different metallicity distribution functions (MDF) trace the accretion history of the Galaxy. By means of N-body simulations, we confirm that accreted stars from a massive merger redistribute in a wide range of E and L z , due to dynamical friction, thus not being associated to a single clump. Since satellite stars with different metallicities can be deposited in different regions of the E−L z space, a single accretion can manifest with different MDFs. This method can bias the merger tree of the Galaxy towards increasing the number of accretions and decreasing the masses of the progenitor galaxies.
SN  - 1743-9213
SN  - 1743-9221
ER  -