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DESI mock challenge: constructing DESI galaxy catalogues based on FastPM simulations

Variu, Andrei; Alam, Shadab; Zhao, Cheng; Chuang, Chia-Hsun; Yu, Yu; Forero-Sánchez, Daniel; Ding, Zhejie; Kneib, Jean-Paul; Aguilar, Jessica Nicole; Ahlen, Steven; Brooks, David; Claybaugh, Todd; Cole, Shaun; Dawson, Kyle; de la Macorra, Axel; Doel, Peter; Forero-Romero, Jaime E; Gontcho, Satya Gontcho A; Honscheid, Klaus; Landriau, Martin; Manera, Marc; Miquel, Ramon; Nie, Jundan; Percival, Will; Poppett, Claire; Rezaie, Mehdi; Rossi, Graziano; Sanchez, Eusebio; Schubnell, Michael; Seo, Hee-Jong; Tarlé, Gregory; Magana, Mariana Vargas; Zhou, Zhimin

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Authors

Andrei Variu

Shadab Alam

Cheng Zhao

Chia-Hsun Chuang

Yu Yu

Daniel Forero-Sánchez

Zhejie Ding

Jean-Paul Kneib

Jessica Nicole Aguilar

Steven Ahlen

David Brooks

Todd Claybaugh

Kyle Dawson

Axel de la Macorra

Peter Doel

Jaime E Forero-Romero

Satya Gontcho A Gontcho

Klaus Honscheid

Martin Landriau

Marc Manera

Ramon Miquel

Jundan Nie

Will Percival

Claire Poppett

Mehdi Rezaie

Graziano Rossi

Eusebio Sanchez

Michael Schubnell

Hee-Jong Seo

Gregory Tarlé

Mariana Vargas Magana

Zhimin Zhou



Abstract

Together with larger spectroscopic surveys such as the Dark Energy Spectroscopic Instrument (DESI), the precision of large scale structure studies and thus the constraints on the cosmological parameters are rapidly improving. Therefore, one must build
realistic simulations and robust covariance matrices. We build galaxy catalogues by applying a halo occupation distribution
(HOD) model upon the FASTPM simulations, such that the resulting galaxy clustering reproduces high-resolution N-body
simulations. While the resolution and halo finder are different from the reference simulations, we reproduce the reference galaxy
two-point clustering measurements – monopole and quadrupole – to a precision required by the DESI Year 1 emission line galaxy
sample down to non-linear scales, i.e. k < 0.5 h Mpc−1 or s > 10 Mpc h−1. Furthermore, we compute covariance matrices based
on the resulting FASTPM galaxy clustering – monopole and quadrupole. We study for the first time the effect of fitting on Fourier
conjugate (e.g. power spectrum) on the covariance matrix of the Fourier counterpart (e.g. correlation function). We estimate the
uncertainties of the two parameters of a simple clustering model and observe a maximum variation of 20 per cent for the different
covariance matrices. Nevertheless, for most studied scales the scatter is between 2 and 10 per cent. Consequently, using the
current pipeline we can precisely reproduce the clustering of N-body simulations and the resulting covariance matrices provide
robust uncertainty estimations against HOD fitting scenarios. We expect our methodology will be useful for the coming DESI
data analyses and their extension for other studies.

Citation

Variu, A., Alam, S., Zhao, C., Chuang, C., Yu, Y., Forero-Sánchez, D., …Zhou, Z. (2024). DESI mock challenge: constructing DESI galaxy catalogues based on FastPM simulations. Monthly Notices of the Royal Astronomical Society, 527(4), 11539-11558. https://doi.org/10.1093/mnras/stad3742

Journal Article Type Article
Acceptance Date Nov 14, 2023
Online Publication Date Dec 4, 2023
Publication Date 2024-02
Deposit Date Mar 18, 2024
Publicly Available Date Mar 18, 2024
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 527
Issue 4
Pages 11539-11558
DOI https://doi.org/10.1093/mnras/stad3742
Keywords Space and Planetary Science; Astronomy and Astrophysics
Public URL https://durham-repository.worktribe.com/output/2331700

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