scholarly journals Peaks in the cosmological density field: sensitivity to initial power spectrum, redshift distortions and galaxy halo occupation

2007 ◽  
Vol 382 (4) ◽  
pp. 1591-1600 ◽  
Author(s):  
S. De ◽  
R. A. C. Croft
Keyword(s):  
Power Spectrum ◽  
Density Field ◽  
Field Sensitivity ◽  
Galaxy Halo ◽  
Initial Power

scholarly journals The galaxy–halo connection in modified gravity cosmologies: environment dependence of galaxy luminosity function

2019 ◽  
Vol 488 (1) ◽  
pp. 782-802 ◽  
Author(s):  
N Chandrachani Devi ◽  
Aldo Rodríguez-Puebla ◽  
O Valenzuela ◽  
Vladimir Avila-Reese ◽  
César Hernández-Aguayo ◽  
...  
Keyword(s):  
Modified Gravity ◽  
Luminosity Function ◽  
Cold Dark Matter ◽  
Density Field ◽  
High Density ◽  
Gravity Models ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Environment Dependence ◽  
Galaxy Luminosity Function

Abstract We investigate the dependence of the galaxy–halo connection and galaxy density field in modified gravity models using the N-body simulations for f(R) and nDGP models at z = 0. Because of the screening mechanisms employed by these models, chameleon and Vainshtein, haloes are clustered differently in the non-linear regime of structure formation. We quantify their deviations in the galaxy density field from the standard Λ cold dark matter (ΛCDM) model under different environments. We populate galaxies in haloes via the (sub)halo abundance matching. Our main results are as follows: (1) The galaxy–halo connection strongly depends on the gravity model; a maximum variation of ${\sim }40{{\ \rm per\ cent}}$ is observed between halo occupational distribution (HOD) parameters; (2) f(R) gravity models predict an excess of galaxies in low-density environments of ${\sim }10{{\ \rm per\ cent}}$ but predict a deficit of ${\sim }10{{\ \rm per\ cent}}$ at high-density environments for |fR0| = 10−4 and 10−6 while |fR0| = 10−5 predicts more high-density structures; nDGP models are consistent with ΛCDM; (3) different gravity models predict different dependences of the galaxy luminosity function (GLF) with the environment, especially in void-like regions we find differences around ${\sim }10{{\ \rm per\ cent}}$ for the f(R) models while nDPG models remain closer to ΛCDM for low-luminosity galaxies but there is a deficit of ${\sim }11{{\ \rm per\ cent}}$ for high-luminosity galaxies in all environments. We conclude that the dependence of the GLF with environment might provide a test to distinguish between gravity models and their screening mechanisms from the ΛCDM. We provide HOD parameters for the gravity models analysed in this paper.

scholarly journals Thermal Sunyaev–Zel’dovich Effect in the IGM due to Primordial Magnetic Fields

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 143 ◽  
Author(s):  
Teppei Minoda ◽  
Kenji Hasegawa ◽  
Hiroyuki Tashiro ◽  
Kiyotomo Ichiki ◽  
Naoshi Sugiyama
Keyword(s):  
Magnetic Fields ◽  
Power Spectrum ◽  
Mass Density ◽  
Temperature Anisotropy ◽  
Angular Power Spectrum ◽  
Stringent Constraint ◽  
Small Scales ◽  
Sunyaev Zel'dovich Effect ◽  
Primordial Magnetic Fields ◽  
Initial Power

In the present universe, magnetic fields exist with various strengths and on various scales. One possible origin of these cosmic magnetic fields is the primordial magnetic fields (PMFs) generated in the early universe. PMFs are considered to contribute to matter density evolution via Lorentz force and the thermal history of intergalactic medium (IGM) gas due to ambipolar diffusion. Therefore, information about PMFs should be included in the temperature anisotropy of the Cosmic Microwave Background through the thermal Sunyaev–Zel’dovich (tSZ) effect in IGM. In this article, given an initial power spectrum of PMFs, we show the spatial fluctuation of mass density and temperature of the IGM and tSZ angular power spectrum created by the PMFs. Finally, we find that the tSZ angular power spectrum induced by PMFs becomes significant on small scales, even with PMFs below the observational upper limit. Therefore, we conclude that the measurement of tSZ anisotropy on small scales will provide the most stringent constraint on PMFs.

scholarly journals Constraining the growth rate of structure with phase correlations

2020 ◽  
Vol 497 (2) ◽  
pp. 1765-1790
Author(s):  
Joyce Byun ◽  
Felipe Oliveira Franco ◽  
Cullan Howlett ◽  
Camille Bonvin ◽  
Danail Obreschkow
Keyword(s):  
Growth Rate ◽  
Correlation Function ◽  
Power Spectrum ◽  
Large Scale ◽  
Large Scale Structure ◽  
Density Field ◽  
Galaxy Surveys ◽  
Additional Information ◽  
Forecasting Method ◽  
The Galaxy

ABSTRACT We show that correlations between the phases of the galaxy density field in redshift space provide additional information about the growth rate of large-scale structure that is complementary to the power-spectrum multipoles. In particular, we consider the multipoles of the line correlation function (LCF), which correlates phases between three collinear points, and use the Fisher forecasting method to show that the LCF multipoles can break the degeneracy between the measurement of the growth rate of structure f and the amplitude of perturbations σ8 that is present in the power-spectrum multipoles at large scales. This leads to an improvement in the measurement of f and σ8 by up to 220 per cent for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{-1}$ and up to 50 per cent for $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{-1}$ at redshift z = 0.25, with respect to power-spectrum measurements alone for the upcoming generation of galaxy surveys like DESI and Euclid. The average improvements in the constraints on f and σ8 for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{-1}$ are ∼90 per cent for the DESI BGS sample with mean redshift $\overline{z}=0.25$, ∼40 per cent for the DESI ELG sample with $\overline{z}=1.25$, and ∼40 per cent for the Euclid Hα galaxies with $\overline{z}=1.3$. For $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{-1}$, the average improvements are ∼40 per cent for the DESI BGS sample and ∼20 per cent for both the DESI ELG and Euclid Hα galaxies.

scholarly journals Bayesian forward modelling of cosmic shear data

2021 ◽  
Vol 502 (2) ◽  
pp. 3035-3044
Author(s):  
Natalia Porqueres ◽  
Alan Heavens ◽  
Daniel Mortlock ◽  
Guilhem Lavaux
Keyword(s):  
Power Spectrum ◽  
Power Spectra ◽  
Density Field ◽  
Matter Distribution ◽  
Bayesian Hierarchical ◽  
Matter Power Spectrum ◽  
Field Samples ◽  
Dark Matter Distribution ◽  
Cosmic Shear ◽  
Non Gaussian

ABSTRACT We present a Bayesian hierarchical modelling approach to infer the cosmic matter density field, and the lensing and the matter power spectra, from cosmic shear data. This method uses a physical model of cosmic structure formation to infer physically plausible cosmic structures, which accounts for the non-Gaussian features of the gravitationally evolved matter distribution and light-cone effects. We test and validate our framework with realistic simulated shear data, demonstrating that the method recovers the unbiased matter distribution and the correct lensing and matter power spectrum. While the cosmology is fixed in this test, and the method employs a prior power spectrum, we demonstrate that the lensing results are sensitive to the true power spectrum when this differs from the prior. In this case, the density field samples are generated with a power spectrum that deviates from the prior, and the method recovers the true lensing power spectrum. The method also recovers the matter power spectrum across the sky, but as currently implemented, it cannot determine the radial power since isotropy is not imposed. In summary, our method provides physically plausible inference of the dark matter distribution from cosmic shear data, allowing us to extract information beyond the two-point statistics and exploiting the full information content of the cosmological fields.

scholarly journals Modified initial power spectrum and too big to fail problem

2020 ◽  
Vol 494 (4) ◽  
pp. 4907-4913 ◽  
Author(s):  
Hamed Kameli ◽  
Shant Baghram
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Power Spectrum ◽  
Initial Conditions ◽  
Dark Matter Halo ◽  
Current Status ◽  
Number Density ◽  
Too Big To Fail ◽  
Standard Case ◽  
Initial Power

ABSTRACT The galactic scale challenges of dark matter such as ‘missing satellite’ problem and ‘too big to fail’ problem are the main caveats of standard model of cosmology. These challenges could be solved either by implementing the complicated baryonic physics or it could be considered as an indication to a new physics beyond the standard model of cosmology. The modification of collisionless dark matter models or the standard initial conditions are two promising venues for study. In this work, we investigate the effects of the deviations from scale invariant initial curvature power spectrum on number density of dark matter haloes. We develop the non-Markov extension of the excursion set theory to calculate the number density of dark matter substructures and dark matter halo progenitor mass distribution. We show that the plausible solution to ‘too big to fail’ problem could be obtained by a Gaussian excess in initial power in the scales of k* ∼ 3 h Mpc−1 that is related to the mass scale of M* ∼ 1011 M⊙. We show that this deviation leads to the decrement of dark matter subhaloes in galactic scale, which is consistent with the current status of the non-linear power spectrum. Our proposal also has a prediction that the number density of Milky Way-type galaxies must be higher than the standard case.

Cosmic Data Fusion

2005 ◽  
Vol 201 ◽  
pp. 368-376
Author(s):  
S. L. Bridle
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Big Bang ◽  
Joint Analysis ◽  
Data Sets ◽  
Cluster Number ◽  
Scale Invariant ◽  
Peculiar Velocities ◽  
Initial Power

We compare and combine likelihood functions of the cosmological parameters Ωm, h and σ8 from the CMB, type Ia supernovae and from probes of large scale structure. We include the recent results from the CMB experiments BOOMERANG and MAXIMA-1. Our analysis assumes a flat ACDM cosmology with a scale-invariant adiabatic initial power spectrum. First we consider three data sets that directly probe the mass in the Universe, without the need to relate the galaxy distribution to the underlying mass via a “biasing” relation: peculiar velocities, CMB and supernovae. We assume a baryonic fraction as inferred from Big-Bang Nucleosynthesis and find that all three data sets agree well, overlapping significantly at the 2σ level. This therefore justifies a joint analysis, in which we find a joint best fit point and 95% confidence limits of Ωm = 0.28 (0.17, 0.39), h = 0.74 (0.64, 0.86), and σ8 = 1.17 (0.98,1.37). Secondly we extend our earlier work on combining CMB, supernovae, cluster number counts, IRAS galaxy redshift survey data to include BOOMERANG and MAXIMA-1 data and to allow a free Ωbh2. We find that, given our assumption of a scale invariant initial power spectrum (n = 1), we obtain the robust result of Ωbh2 = 0.031 ± 0.03, which is dominated by the CMB constraint.

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