The dual origin of stellar halos. II. Chemical abundances as tracers of formation history

Adi Zolotov, Beth Willman, Alyson M. Brooks, Fabio Governato, David W. Hogg, Sijing Shen, James Wadsley

    Research output: Contribution to journalArticle

    Abstract

    Fully cosmological, high-resolution N-body+smooth particle hydrodynamic simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova feedback recipe, as well as metal enrichment, metal cooling, and metal diffusion. As presented in an earlier paper, the simulated galaxies in this study are surrounded by stellar halos whose inner regions contain both stars accreted from satellite galaxies and stars formed in situ in the central regions of the main galaxies and later displaced by mergers into their inner halos. The abundance patterns ([Fe/H] and [O/Fe]) of halo stars located within 10 kpc of a solar-like observer are analyzed. We find that for galaxies which have not experienced a recent major merger, in situ stars at the high [Fe/H] end of the metallicity distribution function are more [α/Fe]-rich than accreted stars at similar [Fe/H]. This dichotomy in the [O/Fe] of halo stars at a given [Fe/H] results from the different potential wells within which in situ and accreted halo stars form. These results qualitatively match recent observations of local Milky Way halo stars. It may thus be possible for observers to uncover the relative contribution of different physical processes to the formation of stellar halos by observing such trends in the halo populations of the Milky Way and other local L* galaxies.

    Original languageEnglish (US)
    Pages (from-to)738-743
    Number of pages6
    JournalAstrophysical Journal
    Volume721
    Issue number1
    DOIs
    StatePublished - Sep 20 2010

    Fingerprint

    tracers
    halos
    tracer
    histories
    stars
    merger
    metal
    history
    galaxies
    simulation
    hydrodynamics
    cooling
    well
    metals
    trends
    in situ
    chemical
    dichotomies
    metallicity
    supernovae

    Keywords

    • Galaxy: abundances
    • Galaxy: formation
    • Galaxy: halo
    • Methods: numerical

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Zolotov, A., Willman, B., Brooks, A. M., Governato, F., Hogg, D. W., Shen, S., & Wadsley, J. (2010). The dual origin of stellar halos. II. Chemical abundances as tracers of formation history. Astrophysical Journal, 721(1), 738-743. https://doi.org/10.1088/0004-637X/721/1/738

    The dual origin of stellar halos. II. Chemical abundances as tracers of formation history. / Zolotov, Adi; Willman, Beth; Brooks, Alyson M.; Governato, Fabio; Hogg, David W.; Shen, Sijing; Wadsley, James.

    In: Astrophysical Journal, Vol. 721, No. 1, 20.09.2010, p. 738-743.

    Research output: Contribution to journalArticle

    Zolotov, A, Willman, B, Brooks, AM, Governato, F, Hogg, DW, Shen, S & Wadsley, J 2010, 'The dual origin of stellar halos. II. Chemical abundances as tracers of formation history', Astrophysical Journal, vol. 721, no. 1, pp. 738-743. https://doi.org/10.1088/0004-637X/721/1/738
    Zolotov, Adi ; Willman, Beth ; Brooks, Alyson M. ; Governato, Fabio ; Hogg, David W. ; Shen, Sijing ; Wadsley, James. / The dual origin of stellar halos. II. Chemical abundances as tracers of formation history. In: Astrophysical Journal. 2010 ; Vol. 721, No. 1. pp. 738-743.
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