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Precision modelling of the matter power spectrum in a Planck-like Universe
journal contribution
posted on 2023-06-09, 17:31 authored by Robert E SmithRobert E Smith, Raul E AnguloWe use a suite of high-resolution N-body simulations and state-of-the-art perturbation theory to improve the code halofit, which predicts the nonlinear matter power spectrum. We restrict attention to parameters in the vicinity of the Planck Collaboration’s best fit. On large-scales (k? 0.07?h?Mpc-1), our model evaluates the 2-loop calculation from the Multi-point Propagator Theory of Bernardeau et al. (2012). On smaller scales (k? 0.7?h?Mpc-1), we transition to a smoothing-spline-fit model, that characterises the differences between the Takahashi et al. (2012) recalibration of halofit2012 and our simulations. We use an additional suite of simulations to explore the response of the power spectrum to variations in the cosmological parameters. In particular, we examine: the time evolution of the dark energy equation of state (w0, wa); the matter density Om; the physical densities of CDM and baryons (?c, ?b); and the primordial power spectrum amplitude As, spectral index ns, and its running a. We construct correction functions, which improve halofit’s dependence on cosmological parameters. Our newly calibrated model reproduces all of our data with ? 1% precision. Including various systematic errors, such as choice of N-body code, resolution, and through inspection of the scaled second order derivatives, we estimate the accuracy to be ? 3% over the hyper-cube: w0 ? { - 1.05, -0.95}, wa ? { - 0.4, 0.4}, Om, 0 ? {0.21, 0.4}, ?c ? {0.1, 0.13}, ?b ? {2.0, 2.4}, ns ? {0.85, 1.05}, As ? {1.72 × 10-9, 2.58 × 10-9}, a ? { - 0.2, 0.2} up to k = 9.0?h?Mpc-1 and out to z = 3. Outside of this range the model reverts to halofit2012. We release all power spectra data with the C-code NGenHalofit at: https://CosmologyCode@bitbucket.org/ngenhalofitteam/ngenhalofitpublic.git.
Funding
University of Sussex Astronomy Consolidated Grant 2017-2020; G2050; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/P000525/1
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Publication status
- Published
File Version
- Published version
Journal
Monthly Notices of the Royal Astronomical SocietyISSN
0035-8711Publisher
Oxford University PressExternal DOI
Issue
1Volume
486Page range
1448-1479Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Astronomy Centre Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2019-04-10First Open Access (FOA) Date
2019-04-10First Compliant Deposit (FCD) Date
2019-04-09Usage metrics
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