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@article{Leclercq:2019:mnras/stz2718,
author = {Leclercq, F and Enzi, W and Jasche, J and Heavens, A},
doi = {mnras/stz2718},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {4237--4253},
title = {Primordial power spectrum and cosmology from black-box galaxy surveys},
url = {http://dx.doi.org/10.1093/mnras/stz2718},
volume = {490},
year = {2019}
}

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TY  - JOUR
AB  - We propose a new, likelihood-free approach to inferring the primordial matterpower spectrum and cosmological parameters from arbitrarily complex forwardmodels of galaxy surveys where all relevant statistics can be determined fromnumerical simulations, i.e. black-boxes. Our approach builds upon approximateBayesian computation using a novel effective likelihood, and upon thelinearisation of black-box models around an expansion point. Consequently, weobtain simple "filter equations" for an effective posterior of the primordialpower spectrum, and a straightforward scheme for cosmological parameterinference. We demonstrate that the workload is computationally tractable, fixeda priori, and perfectly parallel. As a proof of concept, we apply our frameworkto a realistic synthetic galaxy survey, with a data model accounting forphysical structure formation and incomplete and noisy galaxy observations. Indoing so, we show that the use of non-linear numerical models allows the galaxypower spectrum to be safely fitted up to at least $k_\mathrm{max} = 0.5$$h$/Mpc, outperforming state-of-the-art backward-modelling techniques by afactor of $\sim 5$ in the number of modes used. The result is an unbiasedinference of the primordial matter power spectrum across the entire range ofscales considered, including a high-fidelity reconstruction of baryon acousticoscillations. It translates into an unbiased and robust inference ofcosmological parameters. Our results pave the path towards easy applications oflikelihood-free simulation-based inference in cosmology.
AU  - Leclercq,F
AU  - Enzi,W
AU  - Jasche,J
AU  - Heavens,A
DO  - mnras/stz2718
EP  - 4253
PY  - 2019///
SN  - 0035-8711
SP  - 4237
TI  - Primordial power spectrum and cosmology from black-box galaxy surveys
T2  - Monthly Notices of the Royal Astronomical Society
UR  - http://dx.doi.org/10.1093/mnras/stz2718
UR  - https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stz2718/5583010
UR  - http://hdl.handle.net/10044/1/73943
VL  - 490
ER  -

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