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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. Percent-level accurate emulation is now supported in the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Euclid Collaboration , M. Knabenhans , J. Stadel , D. Potter , J. Dakin , S. Hannestad , T. Tram , S. Marelli , A. Schneider , R. Teyssier , S. Andreon , N. Auricchio , C. Baccigalupi , A. Balaguera-Antolínez , M. Baldi , S. Bardelli , P. Battaglia , R. Bender , A. Biviano , C. Bodendorf , E. Bozzo , E. Branchini , M. Brescia , C. Burigana , R. Cabanac , S. Camera , V. Capobianco , A. Cappi , C. Carbone , J. Carretero , C. S. Carvalho , R. Casas , S. Casas , M. Castellano , G. Castignani , S. Cavuoti , R. Cledassou , C. Colodro-Conde , G. Congedo , C. J. Conselice , L. Conversi , Y. Copin , L. Corcione , J. Coupon , H. M. Courtois , A. Da Silva , S. de la Torre , D. Di Ferdinando , C. A. J. Duncan , X. Dupac , G. Fabbian , S. Farrens , P. G. Ferreira , F. Finelli , M. Frailis , E. Franceschi , S. Galeotta , B. Garilli , C. Giocoli , G. Gozaliasl , J. Graciá-Carpio , F. Grupp , L. Guzzo , W. Holmes , F. Hormuth , H. Israel , K. Jahnke , E. Keihanen , S. Kermiche , C. C. Kirkpatrick , B. Kubik , M. Kunz , H. Kurki-Suonio , S. Ligori , P. B. Lilje , I. Lloro , D. Maino , O. Marggraf , K. Markovic , N. Martinet , F. Marulli , R. Massey , N. Mauri , S. Maurogordato , E. Medinaceli , M. Meneghetti , B. Metcalf , G. Meylan , M. Moresco , B. Morin , L. Moscardini , E. Munari , C. Neissner , S. M. Niemi , C. Padilla , S. Paltani , F. Pasian , L. Patrizii , V. Pettorino , S. Pires , G. Polenta , M. Poncet , F. Raison , A. Renzi , J. Rhodes , G. Riccio , E. Romelli , M. Roncarelli , R. Saglia , A. G. Sánchez , D. Sapone , P. Schneider , V. Scottez , A. Secroun , S. Serrano , C. Sirignano , G. Sirri , L. Stanco , F. Sureau , P. Tallada Crespí , A. N. Taylor , M. Tenti , I. Tereno , R. Toledo-Moreo , F. Torradeflot , L. Valenziano , J. Valiviita , T. Vassallo , M. Viel , Y. Wang , N. Welikala , L. Whittaker , A. Zacchei , E. Zucca

N-body simulations are the most powerful method to study the non-linear evolution of large-scale structure. However, they require large amounts of computational resources, making unfeasible their direct adoption in scenarios that require…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-14 Miguel Conceição , Alberto Krone-Martins , Antonio da Silva , Ángeles Moliné

Using an approximate likelihood method adapted to band--power estimates, we analyze the ensemble of first generation cosmic microwave background anisotropy experiments to deduce constraints over a six--dimensional parameter space describing…

Astrophysics · Physics 2011-05-23 M. Le Dour , M. Douspis , J. G. Bartlett , A. Blanchard

Gravitational softening length is one of the key parameters to properly set up a cosmological $N$-body simulation. In this paper, we perform a large suit of high-resolution $N$-body simulations to revise the optimal softening scheme…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-07 Tianchi Zhang , Shihong Liao , Ming Li , Liang Gao

We propose a new numerical procedure to simulate a single dark halo of any size and mass in a hierarchical framework coupling the extended Press-Schechter formalism (EPSF) to N-body simulations. The procedure consists of assigning…

Astrophysics · Physics 2009-11-07 Elena D'Onghia , Claudio Firmani , Guido Chincarini

Initial conditions in cosmological $N$-body simulations are typically generated by displacing particles from a regular cubic lattice using a correlated field derived from the linear power spectrum, often via the Zel'dovich approximation.…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Francesco Sylos Labini

We present the results of a set of cosmological N-body simulations with standard $\Lambda$CDM cosmology but characterized by a scale-dependent primordial non-Gaussianity of the local type featuring a power-law dependence of the $f_{\rm…

In Part I of this series, we introduced the Spherical Collapse (SC) approximation in Lagrangian space as a way of estimating the cumulants $\xi_J$ of density fluctuations in cosmological Perturbation Theory (PT). Within this approximation,…

Astrophysics · Physics 2009-10-30 Enrique Gaztanaga , Pablo Fosalba

The presence of additional relativistic particles at the time of recombination can be inferred through their contribution to $\Delta N_{\rm eff}$. If these species have a finite but low mass (Light Massive Relics - LiMRs), they act as a hot…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-04 Vikhyat Sharma , Arka Banerjee

We test third-order standard perturbation theory (SPT) as an approximation to non-linear cosmological structure formation. A novel approach is used to numerically calculate the three-dimensional dark matter density field using SPT from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Nina Roth , Cristiano Porciani

The applicability of the highly idealized secondary infall model to `realistic' initial conditions is investigated. The collapse of proto-halos seeded by $3\sigma$ density perturbations to an Einstein--de Sitter universe is studied here for…

Astrophysics · Physics 2009-10-28 Saleem Zaroubi , Avi Naim , Yehuda Hoffman

Cosmological N-Body simulations are used for a variety of applications. Indeed progress in the study of large scale structures and galaxy formation would have been very limited without this tool. For nearly twenty years the limitations…

Astrophysics · Physics 2010-05-07 J. S. Bagla , Nishikanta Khandai

Long-range attractive fifth forces can lead to exponential instabilities in the early Universe. For fermions with a Yukawa coupling to a sufficiently light scalar mediator, rapid oscillations of the scalar field can lead to a conservative…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 Derek Inman

We study the structure and substructure of halos obtained in N-body simulations for a Lambda Cold Dark Matter (LCDM) cosmology with non-Gaussian initial conditions (NGICs). The initial statistics are lognormal in the gravitational potential…

Astrophysics · Physics 2008-11-26 V. Avila-Reese , P. Colin , G. Piccinelli , C. Firmani

We present an efficient and accurate method for simulating massive neutrinos in cosmological structure formation simulations, together with an easy to use public implementation. Our method builds on our earlier implementation of the linear…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Simeon Bird , Yacine Ali-Haïmoud , Yu Feng , Jia Liu

Particle-Mesh (PM) codes are still very useful tools for testing predictions of cosmological models in cases when extra high resolution is not very important. We release for public use a cosmological PM N-body code. We provide a complete…

Astrophysics · Physics 2007-05-23 Anatoly Klypin , Jon Holtzman

We devise a fully self-consistent simulation pipeline for the first time to study the interaction between dark matter and dark energy. We perform convergence tests and show that our code is accurate on different scales. Using the parameters…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-03 Jiajun Zhang , Rui An , Shihong Liao , Wentao Luo , Zhaozhou Li , Bin Wang

Modified gravity theories constitute viable alternatives to the standard cosmological model for explaining the observed late-time accelerated expansion of the Universe. The Effective Field Theory of Dark Energy (EFTofDE) is an efficient…

We present the Millennium-II Simulation (MS-II), a very large N-body simulation of dark matter evolution in the concordance LCDM cosmology. The MS-II assumes the same cosmological parameters and uses the same particle number and output data…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-08 Michael Boylan-Kolchin , Volker Springel , Simon D. M. White , Adrian Jenkins , Gerard Lemson

Standard cosmological perturbation theory (SPT) for the Large Scale Structure (LSS) of the Universe fails at small scales (UV) due to strong nonlinearities and to multistreaming effects. In Pietroni et al. 2011 a new framework was proposed…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Alessandro Manzotti , Marco Peloso , Massimo Pietroni , Matteo Viel , Francisco Villaescusa-Navarro