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TRACING GALAXY FORMATION WITH STELLAR HALOS. II. RELATING SUBSTRUCTURE IN PHASE AND ABUNDANCE SPACE TO ACCRETION HISTORIES

Johnston, KV, Bullock, JS, Sharma, S, Font, AS, Robertson, BE and Leitner, SN (2008) TRACING GALAXY FORMATION WITH STELLAR HALOS. II. RELATING SUBSTRUCTURE IN PHASE AND ABUNDANCE SPACE TO ACCRETION HISTORIES. Astrophysical Journal, 689 (2). pp. 936-957. ISSN 0004-637X

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Abstract

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 objects. The study utilizes a suite of eleven stellar halo models constructed within the context of a standard ΛCDM cosmology. The results demonstrate that coordinate-space studies are sensitive to the recent (0-8 Gyears ago) merger histories of galaxies (this timescale corresponds to the last few to tens of percent of mass accretion for a Milky-Way-type galaxy). Specifically, the frequency, sky coverage and fraction of stars in substructures in the stellar halo as a function of surface brightness are indicators of the importance of recent merging and of the luminosity function of infalling dwarfs. The morphology of features serves as a guide to the orbital distribution of those dwarfs. Constraints on the earlier merger history (> 8 Gyears ago) can be gleaned from the abundance patterns in halo stars: within our models, dramatic differences in the dominant epoch of accretion or luminosity function of progenitor objects leave clear signatures in the [α/Fe] and [Fe/H] distributions of the stellar halo — halos dominated by very early accretion have higher average [α/Fe], while those dominated by high luminosity satellites have higher [Fe/H]. This intuition can be applied to reconstruct much about the merger histories of nearby galaxies from current and future data sets.

Item Type: Article
Additional Information: @2008. The American Astronomical Society. All rights reserved. Printed in U.S.A
Uncontrolled Keywords: 0201 Astronomical and Space Sciences, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0306 Physical Chemistry (incl. Structural)
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: American Astronomical Society; IOP Publishing
Related URLs:
Date Deposited: 29 Apr 2021 10:27
Last Modified: 29 Apr 2021 10:27
DOI or Identification number: 10.1086/592228
URI: https://researchonline.ljmu.ac.uk/id/eprint/14886

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