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dc.contributor.authorGarrison, Lehman H.
dc.contributor.authorEisenstein, Daniel J.
dc.contributor.authorFerrer, Douglas
dc.contributor.authorMetchnik, Marc V.
dc.contributor.authorPinto, Philip A.
dc.date.accessioned2016-12-16T00:13:30Z
dc.date.available2016-12-16T00:13:30Z
dc.date.issued2016-10-01
dc.identifier.citationImproving initial conditions for cosmological N -body simulations 2016, 461 (4):4125 Monthly Notices of the Royal Astronomical Societyen
dc.identifier.issn0035-8711
dc.identifier.issn1365-2966
dc.identifier.doi10.1093/mnras/stw1594
dc.identifier.urihttp://hdl.handle.net/10150/621729
dc.description.abstractIn cosmological N-body simulations, the representation of dark matter as discrete 'macroparticles' suppresses the growth of structure, such that simulations no longer reproduce linear theory on small scales near k(Nyquist). Marcos et al. demonstrate that this is due to sparse sampling of modes near k(Nyquist) and that the often-assumed continuum growing modes are not proper growing modes of the particle system. We develop initial conditions (ICs) that respect the particle linear theory growing modes and then rescale the mode amplitudes to account for growth suppression. These ICs also allow us to take advantage of our very accurate N-body code ABACUS to implement second-order Lagrangian perturbation theory (2LPT) in configuration space. The combination of 2LPT and rescaling improves the accuracy of the late-time power spectra, halo mass functions, and halo clustering. In particular, we achieve 1 per cent accuracy in the power spectrum down to k(Nyquist), versus k(Nyquist)/4 without rescaling or k(Nyquist)/13 without 2LPT, relative to an oversampled reference simulation. We anticipate that our 2LPT will be useful for large simulations where fast Fourier transforms are expensive and that rescaling will be useful for suites of medium-resolution simulations used in cosmic emulators and galaxy survey mock catalogues. Code to generate ICs is available at https://github.com/lgarrison/zeldovich-PLT.
dc.description.sponsorshipNational Science Foundation [AST-1313285, 1228509]; US Department of Energy [DE-SC0013718]; FAS Division of Science, Research Computing Group at Harvard Universityen
dc.language.isoenen
dc.publisherOXFORD UNIV PRESSen
dc.relation.urlhttp://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stw1594en
dc.rights© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Societyen
dc.subjectmethods: numericalen
dc.subjectgalaxies: haloesen
dc.subjectlarge-scale structure of Universeen
dc.titleImproving initial conditions for cosmological N -body simulationsen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.identifier.journalMonthly Notices of the Royal Astronomical Societyen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-09-11T16:22:29Z
html.description.abstractIn cosmological N-body simulations, the representation of dark matter as discrete 'macroparticles' suppresses the growth of structure, such that simulations no longer reproduce linear theory on small scales near k(Nyquist). Marcos et al. demonstrate that this is due to sparse sampling of modes near k(Nyquist) and that the often-assumed continuum growing modes are not proper growing modes of the particle system. We develop initial conditions (ICs) that respect the particle linear theory growing modes and then rescale the mode amplitudes to account for growth suppression. These ICs also allow us to take advantage of our very accurate N-body code ABACUS to implement second-order Lagrangian perturbation theory (2LPT) in configuration space. The combination of 2LPT and rescaling improves the accuracy of the late-time power spectra, halo mass functions, and halo clustering. In particular, we achieve 1 per cent accuracy in the power spectrum down to k(Nyquist), versus k(Nyquist)/4 without rescaling or k(Nyquist)/13 without 2LPT, relative to an oversampled reference simulation. We anticipate that our 2LPT will be useful for large simulations where fast Fourier transforms are expensive and that rescaling will be useful for suites of medium-resolution simulations used in cosmic emulators and galaxy survey mock catalogues. Code to generate ICs is available at https://github.com/lgarrison/zeldovich-PLT.


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