scholarly journals CHAM: a fast algorithm of modelling non-linear matter power spectrum in the sCreened HAlo Model

2018 ◽  
Vol 476 (1) ◽  
pp. L65-L68 ◽  
Author(s):  
Bin Hu ◽  
Xue-Wen Liu ◽  
Rong-Gen Cai
Keyword(s):  
Power Spectrum ◽  
Fast Algorithm ◽  
Matter Power Spectrum ◽  
Non Linear

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.

scholarly journals ETHOS – an effective parametrization and classification for structure formation: the non-linear regime at z ≳ 5

2020 ◽  
Vol 498 (3) ◽  
pp. 3403-3419
Author(s):  
Sebastian Bohr ◽  
Jesús Zavala ◽  
Francis-Yan Cyr-Racine ◽  
Mark Vogelsberger ◽  
Torsten Bringmann ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Structure Formation ◽  
Parameter Space ◽  
Broad Class ◽  
High Redshift ◽  
Acoustic Oscillations ◽  
Effective Parameters ◽  
Matter Power Spectrum ◽  
Wide Range ◽  
Non Linear

ABSTRACT We propose two effective parameters that fully characterize galactic-scale structure formation at high redshifts (z ≳ 5) for a variety of dark matter (DM) models that have a primordial cutoff in the matter power spectrum. Our description is within the recently proposed ETHOS framework and includes standard thermal warm DM (WDM) and models with dark acoustic oscillations (DAOs). To define and explore this parameter space, we use high-redshift zoom-in simulations that cover a wide range of non-linear scales from those where DM should behave as CDM (k ∼ 10 h Mpc−1), down to those characterized by the onset of galaxy formation (k ∼ 500 h Mpc−1). We show that the two physically motivated parameters hpeak and kpeak, the amplitude and scale of the first DAO peak, respectively, are sufficient to parametrize the linear matter power spectrum and classify the DM models as belonging to effective non-linear structure formation regions. These are defined by their relative departure from cold DM (kpeak → ∞) and WDM (hpeak = 0) according to the non-linear matter power spectrum and halo mass function. We identify a region where the DAOs still leave a distinct signature from WDM down to z = 5, while a large part of the DAO parameter space is shown to be degenerate with WDM. Our framework can then be used to seamlessly connect a broad class of particle DM models to their structure formation properties at high redshift without the need of additional N-body simulations.

scholarly journals On the road to percent accuracy: non-linear reaction of the matter power spectrum to dark energy and modified gravity

2019 ◽  
Vol 488 (2) ◽  
pp. 2121-2142 ◽  
Author(s):  
M Cataneo ◽  
L Lombriser ◽  
C Heymans ◽  
A J Mead ◽  
A Barreira ◽  
...  
Keyword(s):  
Dark Energy ◽  
Power Spectrum ◽  
Modified Gravity ◽  
Cold Dark Matter ◽  
High Signal ◽  
Linear Perturbation ◽  
Matter Power Spectrum ◽  
Wide Range ◽  
Non Linear ◽  
Better Than

ABSTRACT We present a general method to compute the non-linear matter power spectrum for dark energy (DE) and modified gravity scenarios with per cent-level accuracy. By adopting the halo model and non-linear perturbation theory, we predict the reaction of a lambda cold dark matter (ΛCDM) matter power spectrum to the physics of an extended cosmological parameter space. By comparing our predictions to N-body simulations we demonstrate that with no-free parameters we can recover the non-linear matter power spectrum for a wide range of different w0–wa DE models to better than 1 per cent accuracy out to k ≈ 1 $h \,{\rm Mpc}^{-1}$. We obtain a similar performance for both DGP and f(R) gravity, with the non-linear matter power spectrum predicted to better than 3 per cent accuracy over the same range of scales. When including direct measurements of the halo mass function from the simulations, this accuracy improves to 1 per cent. With a single suite of standard ΛCDM N-body simulations, our methodology provides a direct route to constrain a wide range of non-standard extensions to the concordance cosmology in the high signal-to-noise non-linear regime.

scholarly journals Intensity mapping as a probe of axion dark matter

2020 ◽  
Vol 500 (3) ◽  
pp. 3162-3177
Author(s):  
Jurek B Bauer ◽  
David J E Marsh ◽  
Renée Hložek ◽  
Hamsa Padmanabhan ◽  
Alex Laguë
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Neutral Hydrogen ◽  
Matrix Formalism ◽  
Intensity Mapping ◽  
Matter Power Spectrum ◽  
Wide Range ◽  
Non Linear ◽  
Order Of Magnitude ◽  
Magnitude Improvement

ABSTRACT We consider intensity mapping (IM) of neutral hydrogen (H i) in the redshift range 0 ≲ z ≲ 3 employing a halo model approach where H i is assumed to follow the distribution of dark matter (DM) haloes. If a portion of the DM is composed of ultralight axions, then the abundance of haloes is changed compared to cold DM below the axion Jeans mass. With fixed total H i density, $\Omega _{\rm H\, \rm {\small I}}$, assumed to reside entirely in haloes, this effect introduces a scale-independent increase in the H i power spectrum on scales above the axion Jeans scale, which our model predicts consistent with N-body simulations. Lighter axions introduce a scale-dependent feature even on linear scales due to its suppression of the matter power spectrum near the Jeans scale. We use the Fisher matrix formalism to forecast the ability of future H i surveys to constrain the axion fraction of DM and marginalize over astrophysical and model uncertainties. We find that a HIRAX-like survey is a very reliable IM survey configuration, being affected minimally by uncertainties due to non-linear scales, while the SKA1MID configuration is the most constraining as it is sensitive to non-linear scales. Including non-linear scales and combining a SKA1MID-like IM survey with the Simons Observatory CMB, the benchmark ‘fuzzy DM’ model with ma = 10−22 eV can be constrained at few per cent. This is almost an order of magnitude improvement over current limits from the Ly α forest. For lighter ULAs, this limit improves below 1 per cent, and allows the possibility to test the connection between axion models and the grand unification scale across a wide range of masses.

scholarly journals On the road to per cent accuracy – II. Calibration of the non-linear matter power spectrum for arbitrary cosmologies

2019 ◽  
Vol 490 (4) ◽  
pp. 4826-4840 ◽  
Author(s):  
Benjamin Giblin ◽  
Matteo Cataneo ◽  
Ben Moews ◽  
Catherine Heymans
Keyword(s):  
Power Spectrum ◽  
Initial Conditions ◽  
Power Spectra ◽  
Linear Regime ◽  
The Road ◽  
Matter Power Spectrum ◽  
Non Linear ◽  
Standard Cosmological Model ◽  
Massive Neutrinos ◽  
On The Road

ABSTRACT We introduce an emulator approach to predict the non-linear matter power spectrum for broad classes of beyond-ΛCDM cosmologies, using only a suite of ΛCDM N-body simulations. By including a range of suitably modified initial conditions in the simulations, and rescaling the resulting emulator predictions with analytical ‘halo model reactions’, accurate non-linear matter power spectra for general extensions to the standard ΛCDM model can be calculated. We optimize the emulator design by substituting the simulation suite with non-linear predictions from the standard halofit tool. We review the performance of the emulator for artificially generated departures from the standard cosmology as well as for theoretically motivated models, such as f(R) gravity and massive neutrinos. For the majority of cosmologies we have tested, the emulator can reproduce the matter power spectrum with errors ${\lesssim}1{{\ \rm per\ cent}}$ deep into the highly non-linear regime. This work demonstrates that with a well-designed suite of ΛCDM simulations, extensions to the standard cosmological model can be tested in the non-linear regime without any reliance on expensive beyond-ΛCDM simulations.

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