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Lyα emitters in a cosmological volume II: the impact of the intergalactic medium

Gurung-López, Siddhartha; Orsi, Álvaro A; Bonoli, Silvia; Padilla, Nelson; Lacey, Cedric G; Baugh, Carlton M

Lyα emitters in a cosmological volume II: the impact of the intergalactic medium Thumbnail


Siddhartha Gurung-López

Álvaro A Orsi

Silvia Bonoli

Nelson Padilla


In the near future galaxy surveys will target Lyman alpha emitting galaxies (LAEs) to unveil the nature of dark energy. It has been suggested that the observability of LAEs is coupled to the large scale properties of the intergalactic medium. Such coupling could introduce distortions into the observed clustering of LAEs, adding a new potential difficulty to the interpretation of upcoming surveys. We present a model of LAEs that incorporates Lyα radiative transfer processes in the interstellar and intergalactic medium. The model is implemented in the GALFORM semi-analytic model of galaxy of formation and evolution. We find that the radiative transfer inside galaxies produces selection effects over galaxy properties. In particular, observed LAEs tend to have low metallicities and intermediate star formation rates. At low redshift we find no evidence of a correlation between the spatial distribution of LAEs and the intergalactic medium properties. However, at high redshift the LAEs are linked to the line of sight velocity and density gradient of the intergalactic medium. The strength of the coupling depends on the outflow properties of the galaxies and redshift. This effect modifies the clustering of LAEs on large scales, adding non linear features. In particular, our model predicts modifications to the shape and position of the baryon acoustic oscillation peak. This work highlights the importance of including radiative transfer physics in the cosmological analysis of LAEs.


Gurung-López, S., Orsi, Á. A., Bonoli, S., Padilla, N., Lacey, C. G., & Baugh, C. M. (2020). Lyα emitters in a cosmological volume II: the impact of the intergalactic medium. Monthly Notices of the Royal Astronomical Society, 491(3), 3266-3289.

Journal Article Type Article
Acceptance Date Nov 13, 2019
Online Publication Date Nov 21, 2019
Publication Date Jan 31, 2020
Deposit Date Nov 26, 2019
Publicly Available Date Nov 26, 2019
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 491
Issue 3
Pages 3266-3289


Accepted Journal Article (3.9 Mb)

Copyright Statement
This article has been accepted for publication in the Monthly notices of the Royal Astronomical Society ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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