HACC: Simulating sky surveys on state-of-the-art supercomputing architectures

Habib, Salman; Pope, Adrian; Finkel, Hal; Frontiere, Nicholas; Heitmann, Katrin; Daniel, David; Fasel, Patricia; Morozov, Vitali; Zagaris, George; Peterka, Tom; Vishwanath, Venkatram; Lukić, Zarija; Sehrish, Saba; Liao, Wei

doi:10.1016/j.newast.2015.06.003

Cited by 239 publications

(156 citation statements)

References 66 publications

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“…A single simulation with the required halo mass resolution (∼ 4×10 11 h −1 M , Cochrane et al 2017) that covers the whole volume sampled by Euclid (∼ 70 Gpc 3 ) would demand an enormous number of particles (more than 16, 000 3 in a 4 Gpch −1 box). The largest N-body simula-tions performed so far, e.g., MillenniumXXL (Angulo et al 2012), MICE (Fosalba et al 2015), MultiDark (Klypin et al 2016), Dark Sky (Skillman et al 2014), OuterRim (Habib et al 2016), and FLAGSHIP (Potter et al 2016), are still well below this particle number despite their computational expense.…”

Section: Introductionmentioning

confidence: 98%

UNIT project: Universe N-body simulations for the Investigation of Theoretical models from galaxy surveys

Chuang

Yepes

Kitaura

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present the UNIT N-body cosmological simulations project, designed to provide precise predictions for nonlinear statistics of the galaxy distribution. We focus on characterizing statistics relevant to emission line and luminous red galaxies in the current and upcoming generation of galaxy surveys. We use a suite of precise particle mesh simulations (FastPM) as well as with full N-body calculations with a mass resolution of ∼ 1.2×10 9 h −1 M to investigate the recently suggested technique of Angulo & Pontzen 2016 to suppress the variance of cosmological simulations We study redshift space distortions, cosmic voids, higher order statistics from z = 2 down to z = 0. We find that both two-and three-point statistics are unbiased. Over the scales of interest for baryon acoustic oscillations and redshift-space distortions, we find that the variance is greatly reduced in the two-point statistics and in the cross correlation between halos and cosmic voids, but is not reduced significantly for the three-point statistics. We demonstrate that the accuracy of the two-point correlation function for a galaxy survey with effective volume of 20 (h −1 Gpc) 3 is improved by about a factor of 40, indicating that two pairs of simulations with a volume of 1 (h −1 Gpc) 3 lead to the equivalent variance of ∼150 such simulations. The N-body simulations presented here thus provide an effective survey volume of about seven times the effective survey volume of DESI or Euclid. The data from this project, including dark matter fields, halo catalogues, and their clustering statistics, are publicly available: http://www.unitsims.org.

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Section: Introductionmentioning

confidence: 98%

UNIT project: Universe N-body simulations for the Investigation of Theoretical models from galaxy surveys

Chuang

Yepes

Kitaura

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…It is therefore important to proceed in a controlled manner when designing a new cosmological hydrodynamics code. This paper is the first in a series to expand the gravitational framework of the Hardware/Hybrid Accelerated Cosmology Code (HACC; Habib et al 2016) with a hydro solver equipped with a full suite of subresolution gas physics models capable of scaling to the problem size demanded by upcoming observations. Here we begin with an exclusive focus on the NR case, which serves as an important first step in the systematic process of modeling all of the baryonic physics relevant on cosmological scales.…”

Section: Introductionmentioning

confidence: 99%

The Borg Cube Simulation: Cosmological Hydrodynamics with CRK-SPH

Emberson

Frontiere

Habib

et al. 2019

ApJ

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A challenging requirement posed by next-generation observations is a firm theoretical grasp of the impact of baryons on structure formation. Cosmological hydrodynamic simulations modeling gas physics are vital in this regard. A high degree of modeling flexibility exists in this space making it important to explore a range of methods in order to gauge the accuracy of simulation predictions. We present results from the first cosmological simulation using Conservative Reproducing Kernel Smoothed Particle Hydrodynamics (CRK-SPH). We employ two simulations: one evolved purely under gravity and the other with non-radiative hydrodynamics. Each contains 2 × 2304 3 cold dark matter plus baryon particles in an 800 h −1 Mpc box. We compare statistics to previous non-radiative simulations including power spectra, mass functions, baryon fractions, and concentration. We find self-similar radial profiles of gas temperature, entropy, and pressure and show that a simple analytic model recovers these results to better than 40% over two orders of magnitude in mass. We quantify the level of non-thermal pressure support in halos and demonstrate that hydrostatic mass estimates are biased low by 24% (10%) for halos of mass 10 15 (10 13 ) h −1 M . We compute angular power spectra for the thermal and kinematic Sunyaev-Zel'dovich effects and find good agreement with the low-Planck measurements. Finally, artificial scattering between particles of unequal mass is shown to have a large impact on the gravity-only run and we highlight the importance of better understanding this issue in hydrodynamic applications. This is the first in a simulation campaign using CRK-SPH with future work including subresolution gas treatments.

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“…In the last decades, development of numerical codes (Teyssier 2002;Springel 2005Springel , 2010Klypin et al 2011;Habib et al 2016) and the access to powerful supercomputers enabled the computation of high resolution cosmological simulations over large volumes e.g. MultiDark (MD hereafter, Prada et al 2012); DarkSkies (DS hereafter, Skillman et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Accurate mass and velocity functions of dark matter haloes

Comparat¹,

Prada²,

Yepes³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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N-body cosmological simulations are an essential tool to understand the observed distribution of galaxies. We use the MultiDark simulation suite, run with the Planck cosmological parameters, to revisit the mass and velocity functions. At redshift z = 0, the simulations cover four orders of magnitude in halo mass from ∼ 10 11 M with 8,783,874 distinct halos and 532,533 subhalos. The total volume used is ∼515 Gpc 3 , more than 8 times larger than in previous studies. We measure and model the halo mass function, its covariance matrix w.r.t halo mass and the large scale halo bias. With the formalism of the excursion-set mass function, we explicit the tight interconnection between the covariance matrix, bias and halo mass function. We obtain a very accurate (< 2% level) model of the distinct halo mass function. We also model the subhalo mass function and its relation to the distinct halo mass function. The set of models obtained provides a complete and precise framework for the description of halos in the concordance Planck cosmology. Finally, we provide precise analytical fits of the V max maximum velocity function up to redshift z < 2.3 to push for the development of halo occupation distribution using V max . The data and the analysis code are made publicly available in the Skies and Universes database.

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HACC: Simulating sky surveys on state-of-the-art supercomputing architectures

Cited by 239 publications

References 66 publications

UNIT project: Universe N-body simulations for the Investigation of Theoretical models from galaxy surveys

UNIT project: Universe N-body simulations for the Investigation of Theoretical models from galaxy surveys

The Borg Cube Simulation: Cosmological Hydrodynamics with CRK-SPH

Accurate mass and velocity functions of dark matter haloes

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