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The effect of the intergalactic environment on the observability of Lyα emitters during reionization

Iliev, Ilian T. ; Shapiro, Paul R. ; McDonald, Patrick ; Mellema, Garrelt ; Pen, Ue-Li

In: Monthly Notices of the Royal Astronomical Society, 2008, vol. 391, no. 1, p. 63-83

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    Titre
    • The effect of the intergalactic environment on the observability of Lyα emitters during reionization
    Auteur
    • Iliev, Ilian T.. Universität Zürich, Institut für Theoretische Physik, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
    • Shapiro, Paul R.. Department of Astronomy, University of Texas, Austin, TX 78712-1083, USA
    • McDonald, Patrick. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George Street, Toronto, ON M5S 3H8, Canada
    • Mellema, Garrelt. Stockholm Observatory, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
    • Pen, Ue-Li. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George Street, Toronto, ON M5S 3H8, Canada
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2008, vol. 391, no. 1, p. 63-83. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:295070
    Summary
    Observations of high-redshift Lyα sources are a major tool for studying the high-redshift universe and are one of the most promising ways to constrain the later stages of reionization. The understanding and interpretation of the data is far from straightforward, however. We discuss the effect of the reionizing intergalactic medium (IGM) on the observability of Lyα sources based on large simulations of early structure formation with radiative transfer. This takes into account self-consistently the reionization history, density, velocity and ionization structures and non-linear source clustering. We find that all fields are highly anisotropic and as a consequence there are very large variations in opacity among the different lines of sight. The velocity effects, from both infall and source peculiar velocity are most important for the luminous sources, affecting the line profile and depressing the bright end of the luminosity function. The line profiles are generally asymmetric and the line centres of the luminous sources are always absorbed due to the high density of the local IGM. For both luminous and average sources the damping wing effects are of similar magnitude and remain significant until fairly late, when the IGM is ionized between 30 and 70 per cent by mass. The ionizing flux in the ionized patch surrounding a high-density peak is generally strongly dominated, particularly at late times, by the cluster of faint sources, rather than the central massive galaxy. Our results reproduce well the observed mean opacity of the IGM at z∼ 6. The IGM absorption does not change appreciably the correlation function of sources at high redshift. Our derived luminosity function assuming constant mass-to-light ratio provides an excellent match to the shape of the observed luminosity function at z= 6.6 with faint-end slope of α=−1.5. The resulting mass-to-light ratio implies that the majority of sources responsible for reionization are too faint to be observed by the current surveys