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Related papers: Partitioning the Galactic Halo with Gaussian Mixtu…

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We report the results of an unsupervised decomposition of the local stellar halo in the chemo-dynamical space spanned by the abundance measurements from APOGEE DR17 and GALAH DR3. In our Gaussian Mixture Model, only four independent…

Astrophysics of Galaxies · Physics 2023-01-31 G. C. Myeong , Vasily Belokurov , David S. Aguado , N. Wyn Evans , Nelson Caldwell , James Bradley

Modern theories of galaxy formation predict that the Galactic stellar halo was hierarchically assembled from the accretion and disruption of smaller systems. This hierarchical assembly is expected to produce a high degree of structure in…

The formation of galaxies can be understood in terms of the assembly patterns of each type of galactic component. To perform this kind of analysis, is necessary to define some criteria to separate those components. Decomposition methods…

We investigate the build-up of the accreted stellar and dark matter haloes of Milky Way-like galaxies in APOSTLE suite of cosmological hydrodynamics simulations. We show that the stellar halo is made up primarily of stars stripped from a…

Astrophysics of Galaxies · Physics 2023-02-15 Anna Genina , Alis Deason , Carlos Frenk

Stellar haloes form through the disruption of satellite galaxies over time, making them a promising observable for constraining galaxy merger histories. We use a dynamical decomposition technique to isolate the stellar haloes of Milky…

Astrophysics of Galaxies · Physics 2025-09-03 Katy L. Proctor , Aaron D. Ludlow , Claudia del P. Lagos , Aaron S. G. Robotham

We perform numerical simulations for the formation of the Galactic stellar halo, based on the currently favored cold dark matter (CDM) theory of galaxy formation. Our numerical models, taking into account both dynamical and chemical…

Astrophysics · Physics 2009-11-06 Kenji Bekki , Masashi Chiba

Over the next decade, the astronomical community will be commissioning multiple wide-field observatories well-suited for studying stellar halos in both integrated light and resolved stars. In preparation for this, we use five…

We study the possibility that the Milky Way's cool stellar disc includes mergers with ancient stars. Galaxies are understood to form in a hierarchical manner, where smaller (proto-)galaxies merge into larger ones. Stars in galaxies, like…

Astrophysics of Galaxies · Physics 2022-07-27 Diane K. Feuillet , Sofia Feltzing , Christian Sahlholdt , Thomas Bensby

The stellar halos of dwarf galaxies are becoming an object of interest in the extragalactic community due to their detection in some recent observations. Additionally, new cosmological simulations of very high resolution were performed,…

The standard cosmological scenario predicts a hierarchical formation for galaxies. Many substructures were found in the Galactic halo, identified as clumps in kinematic spaces, like the energy-angular momentum one (E-Lz), under the…

Astrophysics of Galaxies · Physics 2024-10-09 Alice Mori , Paola Di Matteo , Stefania Salvadori , Sergey Khoperskov , Giulia Pagnini , Misha Haywood

This paper explores the mapping between the observable properties of a stellar halo in phase- and abundance-space and the parent galaxy's accretion history in terms of the characteristic epoch of accretion and mass and orbits of progenitor…

(Abridged) We investigate the hypothesis that some fraction of the globular clusters presently observed in the Galactic halo formed in external dwarf galaxies, by means of a detailed comparison between Zinn's "old halo", "young halo", and…

Astrophysics · Physics 2009-11-10 A. D. Mackey , G. F. Gilmore

We improve the identification and isolation of individual stellar populations in the Galactic halo based on an updated set of empirically calibrated stellar isochrones in the Sloan Digital Sky Survey (SDSS) and Pan-STARRS 1 (PS1)…

Astrophysics of Galaxies · Physics 2021-02-10 Deokkeun An , Timothy C. Beers

We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…

If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted ~100-200 luminous satellite galaxies in the past \~12 Gyr. We model this process using a hybrid semi-analytic plus N-body approach…

Astrophysics · Physics 2008-11-26 James S. Bullock , Kathryn V. Johnston

We study the formation of stellar haloes in three Milky Way-mass galaxies using cosmological smoothed particle hydrodynamics simulations, focusing on the subset of halo stars that form in situ, as opposed to those accreted from satellites.…

Astrophysics of Galaxies · Physics 2015-10-28 Andrew P. Cooper , Owen H. Parry , Ben Lowing , Shaun Cole , Carlos Frenk

In a framework where galaxies form hierarchically, extended stellar haloes are predicted to be an ubiquitous feature around Milky Way-like galaxies and to consist mainly of the shredded stellar component of smaller galactic systems. The…

Astrophysics of Galaxies · Physics 2017-12-20 G. Battaglia , P. North , P. Jablonka , M. Shetrone , D. Minniti , M. Díaz , E. Starkenburg , M. Savoy

We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to explore the overall structure and substructure of the stellar halo of the Milky Way using about 4 million color-selected main sequence turn-off stars. We fit…

[Abridged] We present a medium-resolution spectroscopic survey of late-type giant stars at mid-Galactic latitudes of (30$^{\circ}<|b|<60^{\circ}$), designed to probe the properties of this population to distances of $\sim$9 kpc. Because M…

We compare the metallicity distribution of Galactic Halo stars with 3D realizations of hierarchical galaxy formation. Outflows from dwarf galaxies enrich the intergalactic medium inhomogeneously, at a rate depending on the local galaxy…

Astrophysics · Physics 2009-10-31 Evan Scannapieco , Tom Broadhurst