scholarly journals Higher order corrections to the large scale matter power spectrum in the presence of massive neutrinos

2008 ◽  
Vol 2008 (10) ◽  
pp. 035 ◽  
Author(s):  
Yvonne Y Y Wong
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Higher Order ◽  
Matter Power Spectrum ◽  
Massive Neutrinos ◽  
Higher Order Corrections

scholarly journals Modelling the large-scale mass density field of the universe as a function of cosmology and baryonic physics

2020 ◽  
Vol 495 (4) ◽  
pp. 4800-4819 ◽  
Author(s):  
Giovanni Aricò ◽  
Raul E Angulo ◽  
Carlos Hernández-Monteagudo ◽  
Sergio Contreras ◽  
Matteo Zennaro ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Gravitational Lensing ◽  
Large Scale ◽  
Mass Density ◽  
Energy Models ◽  
Matter Power Spectrum ◽  
Non Linear ◽  
Massive Neutrinos ◽  
Hydrodynamical Simulations ◽  
The Universe

ABSTRACT We present and test a framework that models the 3D distribution of mass in the universe as a function of cosmological and astrophysical parameters. Our approach combines two different techniques: a rescaling algorithm that modifies the cosmology of gravity-only N-body simulations, and a ‘baryonification’ algorithm that mimics the effects of astrophysical processes induced by baryons, such as star formation and active galactic nuclei (AGN) feedback. We show how this approach can accurately reproduce the effects of baryons on the matter power spectrum of various state-of-the-art hydrodynamical simulations (EAGLE, Illustris, Illustris-TNG, Horizon-AGN, and OWLS, Cosmo-OWLS and BAHAMAS), to better than 1 per cent from very large down to small, highly non-linear, scales ($k\sim 5 \, h\, {\rm Mpc}^{-1}$), and from z = 0 up to z ∼ 2. We highlight that, because of the heavy optimization of our algorithms, we can obtain these predictions for arbitrary baryonic models and cosmology (including massive neutrinos and dynamical dark energy models) with an almost negligible CPU cost. With these tools in hand, we explore the degeneracies between cosmological and astrophysical parameters in the non-linear mass power spectrum. Our findings suggest that after marginalizing over baryonic physics, cosmological constraints inferred from weak gravitational lensing should be moderately degraded.

scholarly journals Breaking cosmic degeneracies: Disentangling neutrinos and modified gravity with kinematic information

2019 ◽  
Vol 629 ◽  
pp. A46 ◽  
Author(s):  
Steffen Hagstotz ◽  
Max Gronke ◽  
David F. Mota ◽  
Marco Baldi
Keyword(s):  
Growth Rate ◽  
Power Spectrum ◽  
Modified Gravity ◽  
Large Scale ◽  
Density Fluctuations ◽  
Gravity Models ◽  
Neutrino Masses ◽  
Matter Power Spectrum ◽  
Massive Neutrinos ◽  
Kinematic Information

Searches for modified gravity in the large-scale structure try to detect the enhanced amplitude of density fluctuations caused by the fifth force present in many of these theories. Neutrinos, on the other hand, suppress structure growth below their free-streaming length. Both effects take place on comparable scales, and uncertainty in the neutrino mass leads to a degeneracy with modified gravity parameters for probes that are measuring the amplitude of the matter power spectrum. We explore the possibility to break the degeneracy between modified gravity and neutrino effects in the growth of structures by considering kinematic information related to either the growth rate on large scales or the virial velocities inside of collapsed structures. In order to study the degeneracy up to fully non-linear scales, we employ a suite of N-body simulations including both f(R) modified gravity and massive neutrinos. Our results indicate that velocity information provides an excellent tool to distinguish massive neutrinos from modified gravity. Models with different values of neutrino masses and modified gravity parameters possessing a comparable matter power spectrum at a given time have different growth rates. This leaves imprints in the velocity divergence, which is therefore better suited than the amplitude of density fluctuations to tell the models apart. In such models with a power spectrum comparable to ΛCDM today, the growth rate is strictly enhanced. We also find the velocity dispersion of virialised clusters to be well suited to constrain deviations from general relativity without being affected by the uncertainty in the sum of neutrino masses.

scholarly journals Accelerating Large-Scale-Structure data analyses by emulating Boltzmann solvers and Lagrangian Perturbation Theory

2021 ◽  
Vol 1 ◽  
pp. 152
Author(s):  
Giovanni Arico' ◽  
Raul Angulo ◽  
Matteo Zennaro
Keyword(s):  
Perturbation Theory ◽  
Power Spectrum ◽  
Large Scale ◽  
Theoretical Models ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Matter Power Spectrum ◽  
Linear Spectrum ◽  
Massive Neutrinos ◽  
Cold Matter

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 104-106 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 ≤ 3 (z ≤ 9), and scales10-4 ≤ k [h Mpc-1] < 50. We train this emulator with more than 200,000 measurements, spanning a broad cosmological parameter space that includes massive neutrinos and dynamical dark energy. We show that the parameter range and accuracy of our emulator is enough to get unbiased cosmological constraints in the analysis of a Euclid-like weak lensing survey. Complementing this emulator, we train 15 other emulators for the cross-spectra of various linear fields in Eulerian space, as predicted by 2nd-order Lagrangian Perturbation theory, which can be used to accelerate perturbative bias descriptions of galaxy clustering. Our emulators are specially designed to be used in combination with emulators for the nonlinear matter power spectrum and for baryonic effects, all of which are publicly available at http://www.dipc.org/bacco.

scholarly journals On the road to per cent accuracy – III. Non-linear reaction of the matter power spectrum to massive neutrinos

2019 ◽  
Vol 491 (3) ◽  
pp. 3101-3107 ◽  
Author(s):  
M Cataneo ◽  
J D Emberson ◽  
D Inman ◽  
J Harnois-Déraps ◽  
C Heymans
Keyword(s):  
Power Spectrum ◽  
Cold Dark Matter ◽  
New Physics ◽  
Model Reaction ◽  
Matter Power Spectrum ◽  
Non Linear ◽  
Cent Level ◽  
Massive Neutrinos ◽  
On The Road ◽  
Total Matter

ABSTRACT We analytically model the non-linear effects induced by massive neutrinos on the total matter power spectrum using the halo model reaction framework of Cataneo et al. In this approach, the halo model is used to determine the relative change to the matter power spectrum caused by new physics beyond the concordance cosmology. Using standard fitting functions for the halo abundance and the halo mass–concentration relation, the total matter power spectrum in the presence of massive neutrinos is predicted to per cent-level accuracy, out to $k=10 \,{ h}\,{\rm Mpc}^{-1}$. We find that refining the prescriptions for the halo properties using N-body simulations improves the recovered accuracy to better than 1 per cent. This paper serves as another demonstration for how the halo model reaction framework, in combination with a single suite of standard Λ cold dark matter (ΛCDM) simulations, can recover per cent-level accurate predictions for beyond ΛCDM matter power spectra, well into the non-linear regime.

Impact of massive neutrinos on nonlinear matter power spectrum

2008 ◽  
Author(s):  
Shun Saito ◽  
Masahiro Takada ◽  
Atsushi Taruya ◽  
Hideo Kodama ◽  
Kunihito Ioka
Keyword(s):  
Power Spectrum ◽  
Matter Power Spectrum ◽  
Massive Neutrinos

f(R) COSMOLOGY AND MASSIVE NEUTRINOS

2012 ◽  
Vol 10 ◽  
pp. 35-42 ◽  
Author(s):  
HAYATO MOTOHASHI ◽  
ALEXEI A. STAROBINSKY ◽  
JUN'ICHI YOKOYAMA
Keyword(s):  
Equation Of State ◽  
Power Spectrum ◽  
State Parameter ◽  
Density Fluctuations ◽  
Matter Power Spectrum ◽  
Small Scales ◽  
Λcdm Model ◽  
Equation Of State Parameter ◽  
Massive Neutrinos ◽  
Anomalous Growth

f(R) gravity provides viable cosmology alternative to the ΛCDM model. We discuss the effect of massive neutrinos on matter power spectrum in this theory, to show that the anomalous growth of density fluctuations on small scales due to the scalaron force can be compensated by free streaming of neutrinos. As a result, models which predict observable deviation of the equation-of-state parameter w DE from w DE = -1 may be reconciled with observations of matter clustering if the total neutrino mass is O(0.5 eV ).

scholarly journals Mixed dark matter: matter power spectrum and halo mass function

2021 ◽  
Vol 2021 (12) ◽  
pp. 044
Author(s):  
G. Parimbelli ◽  
G. Scelfo ◽  
S.K. Giri ◽  
A. Schneider ◽  
M. Archidiacono ◽  
...  
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Mass Function ◽  
Large Set ◽  
Cluster Number ◽  
Matter Power Spectrum ◽  
Wide Range ◽  
The Impact

Abstract 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, Mwdm, and its fraction with respect to the totality of dark matter, fwdm. The suppression in the matter power spectrum is found to be independent of changes in the cosmological parameters at the 2% level for k≲ 10 h/Mpc and z≤ 3.5. In the same ranges, by applying a baryonification procedure on both ΛCDM and CWDM simulations to account for the effect of feedback, we find a similar level of agreement between the two scenarios. We examine the impact that such suppression has on weak lensing and angular galaxy clustering power spectra. Finally, we discuss the impact of mixed dark matter on the shape of the halo mass function and which analytical prescription yields the best agreement with simulations. We provide the reader with an application to galaxy cluster number counts.

scholarly journals f(R) GRAVITY AND ITS COSMOLOGICAL IMPLICATIONS

2011 ◽  
Vol 20 (08) ◽  
pp. 1347-1355 ◽  
Author(s):  
HAYATO MOTOHASHI ◽  
ALEXEI A. STAROBINSKY ◽  
JUN'ICHI YOKOYAMA
Keyword(s):  
Dark Energy ◽  
Power Spectrum ◽  
Growth Index ◽  
Matter Density ◽  
Cosmic Acceleration ◽  
Matter Power Spectrum ◽  
Density Perturbations ◽  
Massive Neutrinos ◽  
The Universe ◽  
Anomalous Growth

We have investigated the evolution of a homogeneous isotropic background of the Universe and inhomogeneous subhorizon matter density perturbations in viable f(R) models of present dark energy and cosmic acceleration analytically and numerically. It is found that viable f(R) models generically exhibit recent crossing of the phantom boundary w DE = -1. Furthermore, it is shown that the growth index of perturbations depends both on time and wavenumber. This anomalous growth may explain properties of the observational matter power spectrum from the SDSS data and can also partially counteract the spectrum suppression by massive neutrinos making larger values of the total sum of neutrino rest-masses possible.

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