scholarly journals Large‐Scale Power Spectrum from Peculiar Velocities via Likelihood Analysis

1997 ◽  
Vol 486 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Saleem Zaroubi ◽  
Idit Zehavi ◽  
Avishai Dekel ◽  
Yehuda Hoffman ◽  
Tsafrir Kolatt
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Peculiar Velocities ◽  
Likelihood Analysis

Large‐Scale Power Spectrum and Cosmological Parameters from SFI Peculiar Velocities

1999 ◽  
Vol 523 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Wolfram Freudling ◽  
Idit Zehavi ◽  
Luiz N. da Costa ◽  
Avishai Dekel ◽  
Amiram Eldar ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Peculiar Velocities

scholarly journals Anti-symmetric clustering signals in the observed power spectrum

2021 ◽  
Vol 2021 (12) ◽  
pp. 003
Author(s):  
José Fonseca ◽  
Chris Clarkson
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Euler Equation ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Power Spectra ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Signal To Noise ◽  
Peculiar Velocities

Abstract In this paper, we study how to directly measure the effect of peculiar velocities in the observed angular power spectra. We do this by constructing a new anti-symmetric estimator of Large Scale Structure using different dark matter tracers. We show that the Doppler term is the major component of our estimator and we show that we can measure it with a signal-to-noise ratio up to ∼ 50 using a futuristic SKAO HI galaxy survey. We demonstrate the utility of this estimator by using it to provide constraints on the Euler equation.

scholarly journals Large‐Scale Power Spectrum from Peculiar Velocities

1997 ◽  
Vol 479 (2) ◽  
pp. 592-605 ◽  
Author(s):  
Tsafrir Kolatt ◽  
Avishai Dekel
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Peculiar Velocities

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.

scholarly journals Large-Scale Flows in the Local Universe

1996 ◽  
Vol 168 ◽  
pp. 175-182 ◽  
Author(s):  
D.S. Mathewson ◽  
V.L. Ford
Keyword(s):  
Large Scale ◽  
Velocity Measurements ◽  
Local Universe ◽  
Peculiar Velocities ◽  
Redshift Surveys ◽  
Density Maps ◽  
The Universe ◽  
Great Wall ◽  
Great Attractor ◽  
Streaming Flow

Peculiar velocity measurements of 2500 southern spiral galaxies show large-scale flows in the direction of the Hydra-Centaurus clusters which fully participate in the flow themselves. The flow is not uniform over this region and seems to be associated with the denser regions which participate in the flow of amplitude about 400km/s. In the less dense regions the flow is small or non-existent. This makes the flow quite asymmetric and inconsistent with that expected from large-scale, parallel streaming flow that includes all galaxies out to 6000km/s as previously thought. The flow cannot be modelled by a Great Attractor at 4300km/s or the Centaurus clusters at 3500km/s. Indeed, from the density maps derived from the redshift surveys of “optical” and IRAS galaxies, it is difficult to see how the mass concentrations can be responsible particularly as they themselves participate in the flow. These results bring into question the generally accepted reason for the peculiar velocities of galaxies that they arise solely as a consequence of infall into the dense regions of the universe. To the N. of the Great Attractor region, the flow increases and shows no sign of diminishing out to the redshift limit of 8000km/s in this direction. We may have detected flow in the nearest section of the Great Wall.

scholarly journals An Accurate Reconstruction of CMB E Mode Signal over Large Angular Scales using Prior Information of CMB Covariance Matrix in ILC Algorithm

2020 ◽  
Author(s):  
Ujjal Purkayastha ◽  
Vipin Sudevan ◽  
Rajib Saha
Keyword(s):  
Power Spectrum ◽  
Linear Combination ◽  
Covariance Matrix ◽  
Large Scale ◽  
Prior Information ◽  
Future Generation ◽  
Temperature Anisotropy ◽  
Satellite Mission ◽  
Angular Power Spectrum ◽  
Accurate Reconstruction

Abstract Recently, the internal-linear-combination (ILC) method was investigated extensively in the context of reconstruction of Cosmic Microwave Background (CMB) temperature anisotropy signal using observations obtained by WMAP and Planck satellite missions. In this article, we, for the first time, apply the ILC method to reconstruct the large scale CMB E mode polarization signal, which could probe the ionization history, using simulated observations of 15 frequency CMB polarization maps of future generation Cosmic Origin Explorer (COrE) satellite mission. We find that the clean power spectra, from the usual ILC, are strongly biased due to non zero CMB-foregrounds chance correlations. In order to address the issues of bias and errors we extend and improve the usual ILC method for CMB E mode reconstruction by incorporating prior information of theoretical E mode angular power spectrum while estimating the weights for linear combination of input maps (Sudevan & Saha 2018b). Using the E mode covariance matrix effectively suppresses the CMB-foreground chance correlation power leading to an accurate reconstruction of cleaned CMB E mode map and its angular power spectrum. We compare the performance of the usual ILC and the new method over large angular scales and show that the later produces significantly statistically improved results than the former. The new E mode CMB angular power spectrum contains neither any significant negative bias at the low multipoles nor any positive foreground bias at relatively higher mutlipoles. The error estimates of the cleaned spectrum agree very well with the cosmic variance induced error.

scholarly journals The anisotropy of the power spectrum in periodic cosmological simulations

2021 ◽  
Vol 503 (4) ◽  
pp. 5638-5645
Author(s):  
Gábor Rácz ◽  
István Szapudi ◽  
István Csabai ◽  
László Dobos
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Initial Conditions ◽  
Power Spectra ◽  
Cosmological Simulations ◽  
Spherical Collapse ◽  
Lower Amplitude ◽  
Hydrodynamical Simulations

ABSTRACT The classical gravitational force on a torus is anisotropic and always lower than Newton’s 1/r2 law. We demonstrate the effects of periodicity in dark matter only N-body simulations of spherical collapse and standard Lambda cold dark matter (ΛCDM) initial conditions. Periodic boundary conditions cause an overall negative and anisotropic bias in cosmological simulations of cosmic structure formation. The lower amplitude of power spectra of small periodic simulations is a consequence of the missing large-scale modes and the equally important smaller periodic forces. The effect is most significant when the largest mildly non-linear scales are comparable to the linear size of the simulation box, as often is the case for high-resolution hydrodynamical simulations. Spherical collapse morphs into a shape similar to an octahedron. The anisotropic growth distorts the large-scale ΛCDM dark matter structures. We introduce the direction-dependent power spectrum invariant under the octahedral group of the simulation volume and show that the results break spherical symmetry.

scholarly journals Large-scale power spectrum and structures from the ENEAR galaxy peculiar velocity catalogue

2001 ◽  
Vol 326 (1) ◽  
pp. 375-386 ◽  
Author(s):  
S. Zaroubi ◽  
M. Bernardi ◽  
L.N. da Costa ◽  
Y. Hoffman ◽  
M.V. Alonso ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Peculiar Velocity

scholarly journals Using the Marked Power Spectrum to Detect the Signature of Neutrinos in Large-Scale Structure

2021 ◽  
Vol 126 (1) ◽  
Author(s):  
Elena Massara ◽  
Francisco Villaescusa-Navarro ◽  
Shirley Ho ◽  
Neal Dalal ◽  
David N. Spergel
Keyword(s):  
Power Spectrum ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure

scholarly journals Large-Scale Structure in the Universe: Spatial Distribution and Peculiar Velocities

1987 ◽  
Vol 124 ◽  
pp. 335-348
Author(s):  
Neta A. Bahcall
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Clusters Of Galaxies ◽  
Large Scale Structures ◽  
Peculiar Velocities ◽  
Scale Structures ◽  
The Universe

The evidence for the existence of very large scale structures, ∼ 100h−1Mpc in size, as derived from the spatial distribution of clusters of galaxies is summarized. Detection of a ∼ 2000 kms−1 elongation in the redshift direction in the distribution of the clusters is also described. Possible causes of the effect are peculiar velocities of clusters on scales of 10–100h−1Mpc and geometrical elongation of superclusters. If the effect is entirely due to the peculiar velocities of clusters, then superclusters have masses of order 1016.5M⊙ and may contain a larger amount of dark matter than previously anticipated.

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