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Linear bias forecasts for emission line cosmological surveys

Merson, Alexander; Smith, Alex; Benson, Andrew; Wang, Yun; Baugh, Carlton

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Alexander Merson

Alex Smith

Andrew Benson

Yun Wang


We forecast the linear bias for Hα-emitting galaxies at high redshift. To simulate a Euclid-like and a WFIRST-like survey, we place galaxies into a large-volume dark matter halo lightcone by sampling a library of luminosity-dependent halo occupation distributions (HODs), which is constructed using a physically motivated galaxy formation model. We calibrate the dust attenuation in the lightcones such that they are able to reproduce the Hα luminosity function or the Hα cumulative number counts. The angle-averaged galaxy correlation function is computed for each survey in redshift slices of width Δz = 0.2. In each redshift bin the linear bias can be fitted with a single, scale-independent value that increases with increasing redshift. Fitting for the evolution of linear bias with redshift, we find that our Euclid-like and WFIRST-like surveys are both consistent within error with the relation b(z) = 0.7z + 0.7. Our bias forecasts are consistent with bias measurements from the HiZELS survey. We find that the Euclid-like and WFIRST-like surveys yield linear biases that are broadly consistent within error, most likely due to the HOD for the WFIRST-like survey having a steeper power-law slope towards larger halo masses.


Merson, A., Smith, A., Benson, A., Wang, Y., & Baugh, C. (2019). Linear bias forecasts for emission line cosmological surveys. Monthly Notices of the Royal Astronomical Society, 486(4), 5737-5765.

Journal Article Type Article
Acceptance Date Apr 18, 2019
Online Publication Date May 30, 2019
Publication Date Jul 31, 2019
Deposit Date May 7, 2019
Publicly Available Date May 7, 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 486
Issue 4
Pages 5737-5765


Accepted Journal Article (12.6 Mb)

Copyright Statement
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.

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