Probing the matter power spectrum with the galaxy clustering ratio

Gravitational theory of cosmology, galaxies and galaxy clusters

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08482-x ◽

2020 ◽

Vol 80 (10) ◽

Author(s):

J. W. Moffat

Keyword(s):

Power Spectrum ◽

Galaxy Clusters ◽

Degrees Of Freedom ◽

Galaxy Cluster ◽

Gravitational Theory ◽

Baryon Density ◽

Late Time ◽

Matter Power Spectrum ◽

The Galaxy ◽

Parameter Values

AbstractA modified gravitational theory explains early universe and late time cosmology, galaxy and galaxy cluster dynamics. The modified gravity (MOG) theory extends general relativity (GR) by three extra degrees of freedom: a scalar field G, enhancing the strength of the Newtonian gravitational constant $$G_N$$ G N , a gravitational, spin 1 vector graviton field $$\phi _\mu $$ ϕ μ , and the effective mass $$\mu $$ μ of the ultralight spin 1 graviton. For $$t < t_\mathrm{rec}$$ t < t rec , where $$t_\mathrm{rec}$$ t rec denotes the time of recombination and re-ionization, the density of the vector graviton $$\rho _\phi > \rho _b$$ ρ ϕ > ρ b , where $$\rho _b$$ ρ b is the density of baryons, while for $$t > t_\mathrm{rec}$$ t > t rec we have $$\rho _b > \rho _\phi $$ ρ b > ρ ϕ . The matter density is parameterized by $$\Omega _M=\Omega _b+\Omega _\phi +\Omega _r$$ Ω M = Ω b + Ω ϕ + Ω r where $$\Omega _r=\Omega _\gamma +\Omega _\nu $$ Ω r = Ω γ + Ω ν . For the cosmological parameter values obtained by the Planck Collaboration, the CMB acoustical oscillation power spectrum, polarization and lensing data can be fitted as in the $$\Lambda $$ Λ CDM model. When the baryon density $$\rho _b$$ ρ b dominates the late time universe, MOG explains galaxy rotation curves, the dynamics of galaxy clusters, galaxy lensing and the galaxy clusters matter power spectrum without dominant dark matter.

Download Full-text

Simulating galaxy formation in f(R) modified gravity: matter, halo, and galaxy statistics

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2690 ◽

2019 ◽

Vol 490 (2) ◽

pp. 2507-2520 ◽

Cited By ~ 4

Author(s):

Christian Arnold ◽

Baojiu Li

Keyword(s):

Correlation Function ◽

Power Spectrum ◽

Galaxy Formation ◽

Mass Function ◽

Back Reaction ◽

Satellite Galaxy ◽

Matter Power Spectrum ◽

Hydrodynamical Simulation ◽

The Galaxy ◽

Galaxy Count

ABSTRACT We present an analysis of the matter, halo, and galaxy clustering in f(R)-gravity employing the SHYBONE full-physics hydrodynamical simulation suite. Our analysis focuses on the interplay between baryonic feedback and f(R)-gravity in the matter power spectrum, the matter and halo correlation functions, the halo and galaxy–host–halo mass function, the subhalo and satellite–galaxy count, and the correlation function of the stars in our simulations. Our studies of the matter power spectrum in full-physics simulations in f(R)-gravity show that it will be very difficult to derive accurate fitting formulae for the power spectrum enhancement in f(R)-gravity which include baryonic effects. We find that the enhancement of the halo mass function due to f(R)-gravity and its suppression due to feedback effects do not show significant back-reaction effects and can thus be estimated from independent general relativity-hydro and f(R) dark matter only simulations. Our simulations furthermore show that the number of subhaloes and satellite-galaxies per halo is not significantly affected by f(R)-gravity. Low-mass haloes are nevertheless more likely to be populated by galaxies in f(R)-gravity. This suppresses the clustering of stars and the galaxy correlation function in the theory compared to standard cosmology.

Download Full-text

Contributions from primordial non-Gaussianity and general relativity to the galaxy power spectrum

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2021/12/025 ◽

2021 ◽

Vol 2021 (12) ◽

pp. 025

Author(s):

Rebeca Martinez-Carrillo ◽

Juan Carlos Hidalgo ◽

Karim A. Malik ◽

Alkistis Pourtsidou

Keyword(s):

General Relativity ◽

Power Spectrum ◽

Stage Iv ◽

Real Space ◽

Order Effects ◽

Leading Order ◽

Bias Parameter ◽

Matter Power Spectrum ◽

The Galaxy ◽

The One

Abstract We compute the real space galaxy power spectrum, including the leading order effects of General Relativity and primordial non-Gaussianity from the f NL and g NL parameters. Such contributions come from the one-loop matter power spectrum terms dominant at large scales, and from the factors of the non-linear bias parameter b NL (akin to the Newtonian b ϕ). We assess the detectability of these contributions in Stage-IV surveys. In particular, we note that specific values of the bias parameter may erase the primordial and relativistic contributions to the configuration space power spectrum.

Download Full-text

Gravitational Fluctuations as an Alternative to Inflation II. CMB Angular Power Spectrum

10.20944/preprints201910.0101.v1 ◽

2019 ◽

Author(s):

Herbert W. Hamber ◽

Lu Heng Sunny Yu

Keyword(s):

Power Spectrum ◽

Power Spectra ◽

Angular Spectrum ◽

Scalar Fields ◽

Data Sets ◽

Angular Power Spectrum ◽

Fundamental Parameters ◽

Matter Power Spectrum ◽

The Galaxy ◽

Cosmological Data

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum $ P(k) $ and the CMB temperature angular power spectrum $ C_l $’s to high accuracy is often considered a triumph of inflation. In our previous work, we presented an alternative explanation for the matter power spectrum based on nonperturbative quantum field-theoretical methods applied to Einstein’s gravity, instead of inflation models based on scalar fields. In this work, we review the basic concepts and provide further in-depth investigations. We first update the analysis with more recent data sets and error analysis, and then extend our predictions to the CMB angular spectrum coefficients $ C_l $, which we did not consider previously. Then we investigate further the potential freedoms and uncertainties associated with the fundamental parameters that are part of this picture, and show how recent cosmological data provides significant constraints on these quantities. Overall, we find good general consistency between theory and data, even potentially favoring the gravitationally-motivated picture at the largest scales. We summarize our results by outlining how this picture can be tested in the near future with increasingly accurate astrophysical measurements.

Download Full-text

Semi-analytical study on the generic degeneracy for galaxy clustering measurements

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314010771 ◽

2014 ◽

Vol 10 (S306) ◽

pp. 347-350

Author(s):

Alejandro Guarnizo ◽

Luca Amendola ◽

Martin Kunz ◽

Adrian Vollmer

Keyword(s):

Growth Rate ◽

Power Spectrum ◽

Negative Correlation ◽

Analytical Study ◽

Growth Function ◽

Matrix Formalism ◽

Galaxy Clustering ◽

Galaxy Surveys ◽

The Galaxy ◽

Better Than

AbstractFrom the galaxy power spectrum in redshift space, we derive semi-analytical results on the generic degeneracy of galaxy clustering measurements. Defining the observables A = Gbσ8 and R = Gfσ8, (being G the growth function, b the bias, f the growth rate, and σ8 the amplitude of the power spectrum), we perform a Fisher matrix formalism to forecast the expected precision of these quantities for a Euclid-like survey. Among the results we found that galaxy surveys have generically a slightly negative correlation between A and R, and they can always measure R about 3.7 to 4.7 times better than A.

Download Full-text

Gravitational Fluctuations as an Alternative to Inflation II. CMB Angular Power Spectrum

Universe ◽

10.3390/universe5110216 ◽

2019 ◽

Vol 5 (11) ◽

pp. 216 ◽

Cited By ~ 1

Author(s):

Herbert W. Hamber ◽

Lu Heng Sunny Yu

Keyword(s):

Power Spectrum ◽

Power Spectra ◽

Angular Spectrum ◽

Scalar Fields ◽

Data Sets ◽

Angular Power Spectrum ◽

Fundamental Parameters ◽

Matter Power Spectrum ◽

The Galaxy ◽

Cosmological Data

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum P ( k ) and the CMB temperature angular power spectrum C l ’s to high accuracy is often considered a triumph of inflation. In our previous work, we presented an alternative explanation for the matter power spectrum based on nonperturbative quantum field-theoretical methods applied to Einstein’s gravity, instead of inflation models based on scalar fields. In this work, we review the basic concepts and provide further in-depth investigations. We first update the analysis with more recent data sets and error analysis, and then extend our predictions to the CMB angular spectrum coefficients C l , which we did not consider previously. Then we investigate further the potential freedoms and uncertainties associated with the fundamental parameters that are part of this picture, and show how recent cosmological data provides significant constraints on these quantities. Overall, we find good general consistency between theory and data, even potentially favoring the gravitationally-motivated picture at the largest scales. We summarize our results by outlining how this picture can be tested in the near future with increasingly accurate astrophysical measurements.

Download Full-text

Cosmological model parameter dependence of the matter power spectrum covariance from the DEUS-PUR Cosmo simulations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3444 ◽

2020 ◽

Vol 500 (2) ◽

pp. 2532-2542

Author(s):

Linda Blot ◽

Pier-Stefano Corasaniti ◽

Yann Rasera ◽

Shankar Agarwal

Keyword(s):

Dark Energy ◽

Power Spectrum ◽

Cold Dark Matter ◽

Matter Density ◽

Density Fluctuations ◽

Matrix Analysis ◽

Model Parameter ◽

Matter Power Spectrum ◽

Non Gaussian ◽

The Impact

ABSTRACT Future galaxy surveys will provide accurate measurements of the matter power spectrum across an unprecedented range of scales and redshifts. The analysis of these data will require one to accurately model the imprint of non-linearities of the matter density field. In particular, these induce a non-Gaussian contribution to the data covariance that needs to be properly taken into account to realize unbiased cosmological parameter inference analyses. Here, we study the cosmological dependence of the matter power spectrum covariance using a dedicated suite of N-body simulations, the Dark Energy Universe Simulation–Parallel Universe Runs (DEUS-PUR) Cosmo. These consist of 512 realizations for 10 different cosmologies where we vary the matter density Ωm, the amplitude of density fluctuations σ8, the reduced Hubble parameter h, and a constant dark energy equation of state w by approximately $10{{\ \rm per\ cent}}$. We use these data to evaluate the first and second derivatives of the power spectrum covariance with respect to a fiducial Λ-cold dark matter cosmology. We find that the variations can be as large as $150{{\ \rm per\ cent}}$ depending on the scale, redshift, and model parameter considered. By performing a Fisher matrix analysis we explore the impact of different choices in modelling the cosmological dependence of the covariance. Our results suggest that fixing the covariance to a fiducial cosmology can significantly affect the recovered parameter errors and that modelling the cosmological dependence of the variance while keeping the correlation coefficient fixed can alleviate the impact of this effect.

Download Full-text

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3189 ◽

2019 ◽

Vol 491 (3) ◽

pp. 3101-3107 ◽

Cited By ~ 4

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.

Download Full-text