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The properties of Ly-alpha emitting galaxies in hierarchical galaxy formation models

Le Delliou, M.; Lacey, C.G.; Baugh, C.M.; Morris, S.L.

The properties of Ly-alpha emitting galaxies in hierarchical galaxy formation models Thumbnail


M. Le Delliou


We present detailed predictions for the properties of Lyα-emitting galaxies in the framework of the Λ cold dark matter cosmology, calculated using the semi-analytical galaxy formation model galform. We explore a model that assumes a top-heavy initial mass function in starbursts and that has previously been shown to explain the sub-millimetre number counts and the luminosity function of Lyman-break galaxies at high redshift. We show that this model, with the simple assumption that a fixed fraction of Lyα photons escape from each galaxy, is remarkably successful at explaining the observed luminosity function of Lyα emitters (LAEs) over the redshift range 3 < z < 6.6. We also examine the distribution of Lyα equivalent widths and the broad-band continuum magnitudes of emitters, which are in good agreement with the available observations. We look more deeply into the nature of LAEs, presenting predictions for fundamental properties such as the stellar mass and radius of the emitting galaxy and the mass of the host dark matter halo. The model predicts that the clustering of LAEs at high redshifts should be strongly biased relative to the dark matter, in agreement with observational estimates. We also present predictions for the luminosity function of LAEs at z > 7, a redshift range that is starting to be be probed by near-infrared surveys and using new instruments such as the Dark Ages Z Lyman Explorer (DAzLE).

Journal Article Type Article
Publication Date 2006-01
Deposit Date May 2, 2008
Publicly Available Date May 2, 2008
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 365
Issue 3
Pages 712-726
Keywords Galaxies, Evolution, Formation, High-redshift, Luminosity function, Mass function, Cosmology.
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Published Journal Article (385 Kb)

Copyright Statement
This article has been published in the Monthly Notices of the Royal Astronomical Society
© 2005 The Authors.
Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved.

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