Imperial College London
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ProfessorAlanHeavens

Faculty of Natural Sciences, Department of Physics

Chair in Astrostatistics
 
 
 
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Contact

 

+44 (0)20 7594 2930a.heavens Website

 
 
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Location

 

1018EBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Mead:2015:mnras/stv2036,
author = {Mead, AJ and Peacock, JA and Heymans, C and Joudaki, S and Heavens, AF},
doi = {mnras/stv2036},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {1958--1975},
title = {An accurate halo model for fitting non-linear cosmological power spectra and baryonic feedback models},
url = {http://dx.doi.org/10.1093/mnras/stv2036},
volume = {454},
year = {2015}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We present an optimized variant of the halo model, designed to produce accurate matter power spectra well into the non-linear regime for a wide range of cosmological models. To do this, we introduce physically motivated free parameters into the halo-model formalism and fit these to data from high-resolution N-body simulations. For a variety of Λ cold dark matter (ΛCDM) and wCDM models, the halo-model power is accurate to  5 per cent for k ≤ 10h Mpc−1 and z ≤ 2. An advantage of our new halo model is that it can be adapted to account for the effects of baryonic feedback on the power spectrum. We demonstrate this by fitting the halo model to power spectra from the OWLS (OverWhelmingly Large Simulations) hydrodynamical simulation suite via parameters that govern halo internal structure. We are able to fit all feedback models investigated at the 5 per cent level using only two free parameters, and we place limits on the range of these halo parameters for feedback models investigated by the OWLS simulations. Accurate predictions to high k are vital for weak-lensing surveys, and these halo parameters could be considered nuisance parameters to marginalize over in future analyses to mitigate uncertainty regarding the details of feedback. Finally, we investigate how lensing observables predicted by our model compare to those from simulations and from halofit for a range of k-cuts and feedback models and quantify the angular scales at which these effects become important. Code to calculate power spectra from the model presented in this paper can be found at https://github.com/alexander-mead/hmcode.
AU  - Mead,AJ
AU  - Peacock,JA
AU  - Heymans,C
AU  - Joudaki,S
AU  - Heavens,AF
DO  - mnras/stv2036
EP  - 1975
PY  - 2015///
SN  - 1365-2966
SP  - 1958
TI  - An accurate halo model for fitting non-linear cosmological power spectra and baryonic feedback models
T2  - Monthly Notices of the Royal Astronomical Society
UR  - http://dx.doi.org/10.1093/mnras/stv2036
UR  - http://hdl.handle.net/10044/1/33002
VL  - 454
ER  -
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