Title: The DESI N -body simulation project – I. Testing the robustness of simulations for the DESI dark time survey

Abstract

Analysis of large galaxy surveys requires confidence in the robustness of numerical simulation methods. The simulations are used to construct mock galaxy catalogues to validate data analysis pipelines and identify potential systematics. We compare three N-body simulation codes, abacus, gadget-2, and swift, to investigate the regimes in which their results agree. We run N-body simulations at three different mass resolutions, 6.25 × 10⁸, 2.11 × 10⁹, and 5.00 × 10⁹ h^-1 M_⊙, matching phases to reduce the noise within the comparisons. We find systematic errors in the halo clustering between different codes are smaller than the Dark Energy Spectroscopic Instrument (DESI) statistical error for $$s\ \gt\ 20\ h^{-1}$$ Mpc in the correlation function in redshift space. Through the resolution comparison we find that simulations run with a mass resolution of 2.1 × 10⁹ h^-1 M_⊙ are sufficiently converged for systematic effects in the halo clustering to be smaller than the DESI statistical error at scales larger than $$20\ h^{-1}$$ Mpc. These findings show that the simulations are robust for extracting cosmological information from large scales which is the key goal of the DESI survey. Comparing matter power spectra, we find the codes agree to within 1 percent for k ≤ 10 h Mpc^-1. We also run a comparison of three initial condition generation codes and find good agreement. In addition, we include a quasi-N-body code, FastPM, since we plan use it for certain DESI analyses. The impact of the halo definition and galaxy–halo relation will be presented in a follow-up study.

Authors:

Grove, Cameron ;

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• Search DOE PAGES for ORCID "0000-0001-5553-9802"

Chuang, Chia-Hsun ;

• Search DOE PAGES for author "Chuang, Chia-Hsun"
• Search DOE PAGES for ORCID "0000-0002-3882-078X"

Devi, Ningombam Chandrachani; Garrison, Lehman ;

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• Search DOE PAGES for ORCID "0000-0002-9853-5673"

L’Huillier, Benjamin ;

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• Search DOE PAGES for ORCID "0000-0003-2934-6243"

Feng, Yu; Helly, John; Hernández-Aguayo, César ;

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• Search DOE PAGES for ORCID "0000-0001-9921-8832"

Alam, Shadab; Zhang, Hanyu ;

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• Search DOE PAGES for ORCID "0000-0001-6847-5254"

Yu, Yu ;

• Search DOE PAGES for author "Yu, Yu"
• Search DOE PAGES for ORCID "0000-0002-9359-7170"

Cole, Shaun; Eisenstein, Daniel; Norberg, Peder; Wechsler, Risa; Brooks, David; Dawson, Kyle; Landriau, Martin; Meisner, Aaron; Poppett, Claire more »; Tarlé, Gregory; Valenzuela, Octavio « less

Publication Date:

Fri Jul 22 00:00:00 EDT 2022

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP); National Science Foundation (NSF); Science and Technology Facilities Council (STFC); Gordon and Betty Moore Foundation; Heising-Simons Foundation; French Alternative Energies and Atomic Energy Commission (CEA); National Council of Science and Technology,(CONACYT); Ministry of Science and Innovation of Spain (MICINN); National Research Foundation of Korea (NRF); German Research Foundation (DFG)

OSTI Identifier:

1878260

Alternate Identifier(s):

OSTI ID: 1904169; OSTI ID: 1973471

Grant/Contract Number:  

AC02-05CH11231; AST-0950945; ST/P006744/1; NSF AST-1313285; SC0013718; NRF-2019R1I1A1A01063740; EXC-2094-390783311; ST/K00042X/1; ST/P002293/1; ST/R002371/1; ST/S002502/1; ST/R000832/1; SC0019193

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 515 Journal Issue: 2; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; methods; numerical; galaxies; haloes; large-scale structure of Universe; cosmology; theory