The Aemulus Project. I. Numerical Simulations for Precision Cosmology

DeRose, Joseph J.; Wechsler, Risa H.; Tinker, Jeremy L.; Becker, M. R.; Mao, Yao-Yuan; McClintock, Thomas; McLaughlin, Sean; Rozo, Eduardo; Zhai, Zhongxu

doi:10.3847/1538-4357/ab1085

Cited by 138 publications

(112 citation statements)

References 54 publications

(47 reference statements)

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“…It will be crucial, though, to complement this forthcoming data with significant improvements in the modelling of clustering and lensing (see e.g. Wibking et al 2019;DeRose et al 2019;Zhai et al 2019;Nishimichi et al 2018). In addition, further advances will come from combining galaxy clustering and galaxy-galaxy lensing with additional, alternative probes of large-scale structure, such as redshift space distortions (e.g., Yang et al 2008;Reid et al 2014), satellite kinematics (e.g., More et al 2011;Lange et al 2019), higher-order correlation functions (Gil-Marín et al 2017;Gualdi et al 2019), cosmic shear (e.g, Fu et al 2014;Hildebrandt et al 2017), and counts-in-cells (e.g., Reid & Spergel 2009;Gruen et al 2018).…”

Section: Resultsmentioning

confidence: 99%

New perspectives on the BOSS small-scale lensing discrepancy for the Planck ΛCDM cosmology

Lange

Yang

Guo

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We investigate the abundance, small-scale clustering and galaxy-galaxy lensing signal of galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS). To this end, we present new measurements of the redshift and stellar mass dependence of the lensing properties of the galaxy sample. We analyse to what extent models assuming the Planck18 cosmology fit to the number density and clustering can accurately predict the small-scale lensing signal. In qualitative agreement with previous BOSS studies at redshift z ∼ 0.5 and with results from the Sloan Digital Sky Survey, we find that the expected signal at small scales (0.1 < r p < 3 h −1 Mpc) is higher by ∼ 25% than what is measured. Here, we show that this result is persistent over the redshift range 0.1 < z < 0.7 and for galaxies of different stellar masses. If interpreted as evidence for cosmological parameters different from the Planck CMB findings, our results imply S 8 = σ 8 Ω m /0.3 = 0.744 ± 0.015, whereas S 8 = 0.832 ± 0.013 for Planck18. However, in addition to being in tension with CMB results, such a change in cosmology alone does not accurately predict the lensing amplitude at larger scales. Instead, other often neglected systematics like baryonic feedback or assembly bias are likely contributing to the small-scale lensing discrepancy. We show that either effect alone, though, is unlikely to completely resolve the tension. Ultimately, a combination of the two effects in combination with a moderate change in cosmological parameters might be needed.

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Section: Resultsmentioning

confidence: 99%

New perspectives on the BOSS small-scale lensing discrepancy for the Planck ΛCDM cosmology

Lange

Yang

Guo

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The cosmologies of these simulations were sampled using a Latin hypercube method (Heitmann et al 2009) from the joint likelihoods of Planck 2013 and WMAP9 within 4σ confidence intervals. This allows our tests to effectively sample trends of BAO peak systematics across the 7-dimensional hypercube (can be seen in Figure 3 of DeRose et al 2019). A comparison between five of the cosmological parameters against a Planck 2018 + BAO consensus (Alam et al 2017;Planck Collaboration et al 2018) is given in Figure 1.…”

Section: Aemulus Wcdm Simulationsmentioning

confidence: 99%

“…The halos are located using the Rockstar spherical overdensity halo finder (Behroozi et al 2013) selected to have typical radii of ∼ 0.5 − 2h −1 Mpc. In DeRose et al (2019) convergence tests are run to validate the simulations for galaxy clustering studies. Comparisons to training simulations using the HALOFIT algorithm (Smith et al 2003;Takahashi et al 2012) show agreement to better than 1% in mean deviation up to k < 0.3hMpc −1 .…”

Section: Aemulus Wcdm Simulationsmentioning

confidence: 99%

The impact of the fiducial cosmology assumption on BAO distance scale measurements

Carter

Beutler

Percival

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Standard analysis pipelines for measurements of Baryon Acoustic Oscillations (BAO) in galaxy surveys make use of a fiducial cosmological model to guide the data compression required to transform from observed redshifts and angles to the measured angular and radial BAO peak positions. In order to remove any dependence on the fiducial cosmology from the results, all models compared to the data should mimic the compression and its dependence on the fiducial model. In practice, approximations are made when testing models: (1) There is assumed to be no residual dependence on the fiducial cosmology after reconstruction, (2) differences in the distance-redshift relationship are assumed to match a linear scaling, and (3) differences in clustering between true and fiducial models are assumed to be removed by the free parameters used to null the non-BAO signal. We test these approximations using the current standard measurement procedure with a set of halo catalogs from the Aemulus suite of N-body simulations, which span a range of wCDM cosmological models. We focus on reconstruction of the primordial BAO and locating the BAO. For the range of wCDM cosmologies covered by the Aemulus suite, we find no evidence for systematic errors in the measured BAO shift parameters α and α ⊥ to < 0.1%. However, the measured errors σ α and σ α ⊥ show a notable absolute increase by up to +0.001 and +0.002 respectively in the case that the fiducial cosmology does not match the truth. These effects on the inferred BAO scale will be important given the precision of measurements expected from future surveys including DESI, Euclid, and WFIRST.

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“…Several emulators are available already. Examples are FrankenEmu (Heitmann et al 2009(Heitmann et al , 2010(Heitmann et al , 2014, CosmicEmu (Heitmann et al 2016;Lawrence et al 2017), the emulators of the Aemulus project (DeRose et al 2019;McClintock et al 2019;Zhai et al 2019), NGenHalofit (Smith & Angulo 2019), EuclidEmulator1 (Euclid Collaboration: Knabenhans et al 2019), the Dark quest emulator (Nishimichi et al 2019) and BE-HaPPY (Valcin et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Euclid preparation: IX. EuclidEmulator2 – power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

Knabenhans

Stadel

Potter

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. 2 per cent-level accurate emulation is now supported in the eight-dimensional parameter space of w0waCDM+∑mν models between redshift z = 0 and z = 3 for spatial scales within the range 0.01 h Mpc−1 ≤ k ≤ 10 h Mpc−1. In order to achieve this level of accuracy, we have had to improve the quality of the underlying N-body simulations used as training data: (i) we use self-consistent linear evolution of non-dark matter species such as massive neutrinos, photons, dark energy and the metric field, (ii) we perform the simulations in the so-called N-body gauge, which allows one to interpret the results in the framework of general relativity, (iii) we run over 250 high-resolution simulations with 30003 particles in boxes of 1(h−1 Gpc)3 volumes based on paired-and-fixed initial conditions and (iv) we provide a resolution correction that can be applied to emulated results as a post-processing step in order to drastically reduce systematic biases on small scales due to residual resolution effects in the simulations. We find that the inclusion of the dynamical dark energy parameter wa significantly increases the complexity and expense of creating the emulator. The high fidelity of EuclidEmulator2 is tested in various comparisons against N-body simulations as well as alternative fast predictors like HALOFIT, HMCode and CosmicEmu. A blind test is successfully performed against the Euclid Flagship v2.0 simulation. Nonlinear correction factors emulated with EuclidEmulator2 are accurate at the level of $1{{\ \rm per\ cent}}$ or better for 0.01 h Mpc−1 ≤ k ≤ 10 h Mpc−1 and z ≤ 3 compared to high-resolution dark matter only simulations. EuclidEmulator2 is publicly available at https://github.com/miknab/EuclidEmulator2.

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The Aemulus Project. I. Numerical Simulations for Precision Cosmology

Cited by 138 publications

References 54 publications

New perspectives on the BOSS small-scale lensing discrepancy for the Planck ΛCDM cosmology

New perspectives on the BOSS small-scale lensing discrepancy for the Planck ΛCDM cosmology

The impact of the fiducial cosmology assumption on BAO distance scale measurements

Euclid preparation: IX. EuclidEmulator2 – power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

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