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Modelling the observed luminosity function and clustering evolution of Ly α emitters: Growing evidence for late reionization

Accepted version
Peer-reviewed

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Article

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Authors

Weinberger, LH 
Haehnelt, MG 
Kulkarni, G 

Abstract

We model the high redshift (z > 5) Lyman-α emitting (LAE) galaxy population using the empirical rest-frame equivalent width distribution. We calibrate to the observed luminosity function and angular correlation function at z = 5.7 as measured by the SILVERRUSH survey. This allows us to populate the high-dynamic-range Sherwood simulation suite with LAEs, and to calculate the transmission of their Ly α emission through the inter-galactic medium (IGM). We use this simulated population to explore the effect of the IGM on high-redshift observations of LAEs, and make predictions for the narrowband filter redshifts at z = 6.6, 7.0 and 7.3. Comparing our model with existing observations, we find a late reionization is suggested, consistent with the recent low optical depth derived from the cosmic microwave background (CMB) by the Planck collaboration and the opacity fluctuations in the Ly α forest. We also explore the role of the circum-galactic medium (CGM) and the larger volume of gas which is infalling onto the host halo versus the IGM in attenuating the Ly α signal, finding that a significant fraction of the attenuation is due to the CGM and infalling gas, which increases towards the end of reionization, albeit with a large scatter across the mock LAE population.

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Keywords

galaxies: evolution, galaxies: high-redshift, intergalactic medium, dark ages, reionization, first stars, cosmology: theory

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

485

Publisher

Oxford University Press (OUP)
Sponsorship
European Research Council (320596)
Science and Technology Facilities Council (ST/N000927/1)
Science and Technology Facilities Council (ST/M007065/1)
Science and Technology Facilities Council (ST/R002452/1)
Science and Technology Facilities Council (ST/R00689X/1)
Science and Technology Facilities Council (1791046)
STFC (ST/M007073/1)
STFC (ST/T001550/1)