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Faint dwarfs as a test of DM models: WDM versus CDM

Governato, F. ; Weisz, D. ; Pontzen, A. ; Loebman, S. ; Reed, D. ; Brooks, A. M. ; Behroozi, P. ; Christensen, C. ; Madau, P. ; Mayer, L. ; Shen, S. ; Walker, M. ; Quinn, T. ; Keller, B. W. ; Wadsley, J.

In: Monthly Notices of the Royal Astronomical Society, 2015, vol. 448, no. 1, p. 792-803

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    Titre
    • Faint dwarfs as a test of DM models: WDM versus CDM
    Auteur
    • Governato, F.. Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580, USA
    • Weisz, D.. Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580, USA
    • Pontzen, A.. UCL, Department of Physics & Astronomy, Gower Place, London WC1E 6BT, UK
    • Loebman, S.. UCL, Department of Physics & Astronomy, Gower Place, London WC1E 6BT, UK
    • Reed, D.. Institut de Ciències de l'Espai (ICE, IEEC-CSIC), E-08193 Bellaterra (Barcelona), Spain
    • Brooks, A. M.. Department of Physics & Astronomy, Rutgers Univ. 136 Frelinghuysen Rd, Piscataway, NJ 08854, USA
    • Behroozi, P.. UCL, Department of Physics & Astronomy, Gower Place, London WC1E 6BT, UK
    • Christensen, C.. Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Rm. N204, Tucson, AZ 85721-0065, USA
    • Madau, P.. Department of Astronomy, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
    • Mayer, L.. Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zürich, Switzerland Physics Institute, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
    • Shen, S.. Department of Astronomy, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
    • Walker, M.. McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
    • Quinn, T.. Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580, USA
    • Keller, B. W.. Department of Physics and Astronomy, McMaster Univ., Hamilton, Ontario, L88 4M1 CA, USA
    • Wadsley, J.. Department of Physics and Astronomy, McMaster Univ., Hamilton, Ontario, L88 4M1 CA, USA
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2015, vol. 448, no. 1, p. 792-803. Oxford University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:300030
    Summary
    We use high-resolution Hydro+N-Body cosmological simulations to compare the assembly and evolution of a small field dwarf (stellar mass ∼106−7M⊙, total mass 1010M⊙) in Λ-dominated cold dark matter (CDM) and 2keV warm dark matter (WDM) cosmologies. We find that star formation (SF) in the WDM model is reduced and delayed by 1-2Gyr relative to the CDM model, independently of the details of SF and feedback. Independent of the dark matter (DM) model, but proportionally to the SF efficiency, gas outflows lower the central mass density through ‘dynamical heating', such that all realizations have circular velocities <20 km s−1 at 500pc, in agreement with local kinematic constraints. As a result of dynamical heating, older stars are less centrally concentrated than younger stars, similar to stellar population gradients observed in nearby dwarf galaxies. Introducing an important diagnostic of SF and feedback models, we translate our simulations into artificial colour-magnitude diagrams and star formation histories (SFHs) in order to directly compare to available observations. The simulated galaxies formed most of their stars in many ∼10Myr long bursts. The CDM galaxy has a global SFH, H i abundance and Fe/H and alpha-elements distribution well matched to current observations of dwarf galaxies. These results highlight the importance of directly including ‘baryon physics' in simulations when (1) comparing predictions of galaxy formation models with the kinematics and number density of local dwarf galaxies and (2) differentiating between CDM and non-standard models with different DM or power spectra