Understanding the redshift evolution of the luminosity functions of Lyman-alpha emitters

Abstract

We present a semi-analytical model of star formation which explains simultaneously the observed UV luminosity function of high redshift Lyman break galaxies (LBGs) and luminosity functions of Lyman-alpha emitters. We consider both models that use the Press-Schechter (PS) and Sheth-Tormen (ST) halo mass functions to calculate the abundances of dark matter halos. The Lyman-alpha luminosity functions at z < 4 are well reproduced with only <10% of the LBGs emitting Lyman-alpha lines with rest equivalent width greater than the limiting equivalent width of the narrow band surveys. However, the observed luminosity function at z > 5 can be reproduced only when we assume that nearly all LBGs are Lyman-alpha emitters. Thus it appears that 4 < z < 5 marks the epoch when a clear change occurs in the physical properties of the high redshift galaxies. As Lyman-alpha escape depends on dust and gas kinematics of the inter stellar medium (ISM), this could mean that on an average the ISM at z > 5 could be less dusty, more clumpy and having more complex velocity field. All of these will enable easier escape of the Lyman-alpha photons. At z > 5 the observed Lyman-alpha luminosity function are well reproduced with the evolution in the halo mass function along with very minor evolution in the physical properties of high redshift galaxies. In particular, upto z = 6.5, we do not see the effect of evolving inter galactic medium (IGM) opacity on the Lyman-alpha escape from these galaxies.

9 pages, 4 figures, 2 tables, Accepted for publication in MNRAS

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Cited by in corpus (20)

• The Luminosity Function of Lyman alpha Emitters at Redshift z=7.7
• A physical model for the evolving UV luminosity function of high redshift galaxies and their contribution to the cosmic reionization
• Modelling high redshift Lyman-alpha Emitters
• Probing Cosmic Reionization and Molecular Gas Growth with TIME
• The visibility of Lyman Alpha Emitters: constraining reionization, ionizing photons and dust
• Efficient cold outflows driven by cosmic rays in high redshift galaxies and their global effects on the IGM
• Estimating Luminosity Function Constraints from High-Redshift Galaxy Surveys
• Effect of Intergalactic Medium on the Observability of Lyman Alpha Emitters during Cosmic Reionization
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• First study of reionization in the Planck 2015 normalized closed $\Lambda$CDM inflation model
• Spatial Clustering of High Redshift Lyman Break Galaxies
• Clustering and lifetime of Lyman Alpha Emitters in the Epoch of Reionization
• Clustering at high redshift: The connection between Lyman Alpha emitters and Lyman break galaxies
• First study of reionization in tilted flat and untilted non-flat dynamical dark energy inflation models
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• A physical model for the redshift evolution of high-z Lyman-Break Galaxies
• On the star formation efficiency in high redshift Lyman-α emitters
• Observations of Ly$\alpha$ Emitters at High Redshift
• Predicting the Merger Fraction of Lyman alpha Emitters from Redshift z~3 to z~7
• Exploring the Voids: Luminosity Functions and Magnetic Field