We present a neural-network emulator for baryonic effects in the non-linear matter power spectrum. We calibrate this emulator using more than 50,000 measurements in a 15-dimensional parameters space, varying cosmology and baryonic physics. Baryonic physics is described through a baryonification algorithm, that has been shown to accurately capture the relevant effects on the power spectrum and bispectrum in state-of-the-art hydrodynamical simulations. Cosmological parameters are sampled using a cosmology-rescaling approach including massive neutrinos and dynamical dark energy. The specific quantity we emulate is the ratio between matter power spectrum with baryons and gravity-only, and we estimate the overall precision of the emulator to be 1-2%, at all scales 0.01 < k < 5 h/Mpc, and redshifts 0 < z < 1.5. We also obtain an accuracy of 1-2%, when testing the emulator against a collection of 74 different cosmological hydrodynamical simulations and their respective gravity-only counterparts. We show also that only one baryonic parameter, namely Mc, which set the gas fraction retained per halo mass, is enough to have accurate and realistic predictions of the baryonic feedback at a given epoch. Our emulator will become publicly available in http://www.dipc.org/bacco.
We present an emulator that accurately predicts the power spectrum of galaxies in redshift space as a function of cosmological parameters. Our emulator is based on a 2nd-order Lagrangian bias expansion that is displaced to Eulerian space using cosmological $N$-body simulations. Redshift space distortions are then imprinted using the non-linear velocity field of simulated particles and haloes. We build the emulator using a forward neural network trained with the simulations of the BACCO project, which covers an 8-dimensional parameter space including massive neutrinos and dynamical dark energy.…
We present the BACCO project, a simulation framework specially designed to provide highly-accurate predictions for the distribution of mass, galaxies, and gas as a function of cosmological parameters. In this paper, we describe our main suite of simulations (L $\sim2$ Gpc and $4320^3$ particles) and present various validation tests. Using a cosmology-rescaling technique, we predict the nonlinear mass power spectrum over the redshift range $0<z<1.5$ and over scales $10^{-2} < k/(h Mpc^{-1} ) < 5$ for 800 points in an 8-dimensional cosmological parameter space. For an efficient interpolation of …
Balancing bias, baryons, and scale cuts in LSST 3x2pt analysis
University of Edinburgh（爱丁堡大学）；Duke University（杜克大学）；Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology（巴塞罗那高等物理研究所（IFAE），巴塞罗那科学技术学院）
The linear matter power spectrum is an essential ingredient in all theoretical models for interpreting large-scale-structure observables. Although Boltzmann codes such as CLASS or CAMB are very efficient at computing the linear spectrum, the analysis of data usually requires $10^4$-$10^6$ evaluations, which means this task can be the most computationally expensive aspect of data analysis. Here, we address this problem by building a neural network emulator that provides the linear theory (total and cold) matter power spectrum in about one millisecond with 0.2% (0.5%) accuracy over redshifts $z …
syren-baryon: Analytic emulators for the impact of baryons on the matter power spectrum
Evolutionary Algorithms Laboratory, University of Applied Sciences Upper Austria, Hagenberg, Austria Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK Institute of Cosmology \& Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX, UK
Baryonic feedback effects consist of a major systematic for upcoming weak-lensing and galaxy-clustering surveys. In this paper, we present an emulator for the baryonic suppression of the matter power spectrum. The emulator is based on the baryonification model, containing seven free parameters that are connected to the gas profiles and stellar abundances in haloes. We show that with the baryonic emulator, we can not only recover the power spectra of hydro-dynamical simulations at sub-percent precision but also establish a connection between the baryonic suppression of the power spectrum and th…
We compare and validate COLA (COmoving Lagrangian Acceleration) simulations against existing emulators in the literature, namely Bacco and Euclid Emulator 2. Our analysis focuses on the non-linear response function, i.e., the ratio between the non-linear dark matter power spectrum in a given cosmology with respect to a pre-defined reference cosmology, which is chosen to be the Euclid Emulator 2 reference cosmology in this paper. We vary three cosmological parameters, the total matter density, the amplitude of the primordial scalar perturbations and the spectral index. By comparing the COLA non…
A precise symbolic emulator of the linear matter power spectrum
CNRS（法国国家科学研究中心）；Sorbonne Université（索邦大学）；Institut d’Astrophysique de Paris (IAP)（巴黎天体物理研究所）；Heuristic and Evolutionary Algorithms Laboratory（启发式与进化算法实验室）；University of Applied Sciences Upper Austria（上奥地利应用科学大学）；Institute of Cosmology & Gravitation（宇宙学与引力研究所）；University of Portsmouth（朴茨茅斯大学）；University of Oxford（牛津大学）；Center for Computational Astrophysics（计算天体物理中心）；Flatiron Institute（弗拉蒂伦研究所）
syren-halofit: A fast, interpretable, high-precision formula for the $Λ$CDM nonlinear matter power spectrum
CNRS（法国国家科学研究中心）；Sorbonne Université（索邦大学）；Center for Computational Astrophysics, Flatiron Institute（弗拉蒂伦研究所计算天体物理中心）；University of Oxford（牛津大学）；Institute of Cosmology & Gravitation, University of Portsmouth（朴茨茅斯大学宇宙学与引力研究所）
Euclid: An emulator for baryonic effects on the matter bispectrum
University of Waterloo（滑铁卢大学）；INFN-Sezione di Bologna（博洛尼亚意大利国家核物理研究所分部）；University of Zurich（苏黎世大学）；Universität Innsbruck（因斯布鲁克大学）；Donostia International Physics Center (DIPC)（多诺斯蒂亚国际物理中心）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）；Leiden University（莱顿大学）；Oxford University（牛津大学）；University of Cambridge（剑桥大学）
Web-Halo Model (WHM): Accurate non-linear matter power spectrum predictions without free parameters
Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理研究所）；Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University（亚琛工业大学理论粒子物理与宇宙学研究所）
Baryonic feedback effects lead to a suppression of the weak lensing angular power spectrum on small scales. The poorly constrained shape and amplitude of this suppression is an important source of uncertainties for upcoming cosmological weak lensing surveys such as Euclid or LSST. In this first paper in a series of two, we use simulations to build a Euclid-like tomographic mock data-set for the cosmic shear power spectrum and the corresponding covariance matrix, which are both corrected for baryonic effects following the baryonification method of Schneider et al. (2019). In addition, we develo…
We investigate and quantify the impact of mixed (cold and warm) dark matter models on large-scale structure observables. In this scenario, dark matter comes in two phases, a cold one (CDM) and a warm one (WDM): the presence of the latter causes a suppression in the matter power spectrum which is allowed by current constraints and may be detected in present-day and upcoming surveys. We run a large set of $N$-body simulations in order to build an efficient and accurate emulator to predict the aforementioned suppression with percent precision over a wide range of values for the WDM mass, $M_\math…
Biased tracers, Hybrid Effective Field Theory and Modified Gravity
CBPF - Brazilian Center for Research in Physics（巴西物理研究中心）；Institute for Computational Cosmology, Department of Physics, Durham University（杜伦大学）；Institute of Cosmology and Gravitation, University of Portsmouth（朴茨茅斯大学）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学）；Yukawa Institute for Theoretical Physics, Kyoto University（京都大学）
In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, percent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from $Λ$CDM. Massive neutrino and baryonic physics are two of the most relevant such effects. We present an integration of the halo model reaction frameworks for massive neutrinos and beyond-$Λ$CDM cosmologies. The integrated halo model reaction, combined with a pseud…
Euclid preparation. Galaxy power spectrum modelling in redshift space
IFPU, Institute for Fundamental Physics of the Universe（基础物理宇宙研究所）；SISSA, International School for Advanced Studies（国际高等研究学院）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究学院）；INAF-Osservatorio Astronomico di Trieste（的里雅斯特天文台）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文学研究所）；Donostia International Physics Center (DIPC)（圣塞巴斯蒂安国际物理中心）；IKERBASQUE, Basque Foundation for Science（巴斯克科学基金会）；INAF-Osservatorio Astronomico di Brera（布雷拉天文台）；Universität Bonn, Argelander-Institut für Astronomie（波恩大学阿尔兰德天文学研究所）
