Exploring the diversity and similarity of radially anisotropic Milky Way-like stellar haloes: Implications for disrupted dwarf galaxy searches
We investigate the properties of mergers comparable to the Gaia–Sausage–Enceladus (GSE) using cosmological hydrodynamical simulations of Milky Way-like galaxies. The merger progenitors span an order of magnitude in their peak stellar mass(3 × 108 < M/M < 4 × 109) and include both rotation and...
| Autores: | , , , , , , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2023 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositório: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/347857 |
| Acesso em linha: | http://hdl.handle.net/10261/347857 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Methods: numerical Galaxy: abundances Galaxy: centre Galaxy: evolution Galaxy: kinematics and dynamics Galaxy: structure |
| Resumo: | We investigate the properties of mergers comparable to the Gaia–Sausage–Enceladus (GSE) using cosmological hydrodynamical simulations of Milky Way-like galaxies. The merger progenitors span an order of magnitude in their peak stellar mass(3 × 108 < M/M < 4 × 109) and include both rotation and pressure-supported galaxies (0.10 < D/T < 0.77). In a minority of cases, the GSE-like debris is comprised of stars from more than one merger progenitor. However, there is a close similarity in their chemodynamical properties and the triaxial shapes of their debris, and so it is not always possible to distinguish them. The merger progenitors host a variety of luminous satellites (0 and 8 with M > 106 M), but most of these do not follow the merger to low orbital energies. Between 0 and 1 of these satellites may survive to z = 0, but with no clear signatures of their past association. We show that the fraction of stars originating from GSE-like mergers is reduced for lower metallicities (reaching a minimum around [Fe/H] = −2), and also within 5 kpc of the Galactic Centre. Whilst these central regions are dominated by in-situ stars, the ex-situ fraction trends towards a 100 per cent asymptote when considering the most metal-poor stars ([Fe/H] −2.5). Considering this, its near proximity, and its small volume on the sky, the Galactic Centre lends itself as a prime environment in the search for the stars from the earliest galaxies, whilst avoiding contamination from GSE stars. |
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