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Angular power spectra are central to the study of our Universe. In this paper, I develop a new method for the numeric evaluation and analytic estimation of the angular cross-power spectrum of two random fields using complex analysis and…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-27 Job Feldbrugge

The APM Galaxy Survey maps the angular positions of more than one million galaxies to $b_{J} = 20$, covering a volume comparable to the forthcoming Sloan Digital Sky Survey. A numerical algorithm has been developed to estimate the power…

Astrophysics · Physics 2007-05-23 C. M. Baugh , E. Gaztanaga

The anisotropies in the galaxy two-point correlation function measured from redshift surveys exhibits deviations from the predictions of the linear theory of redshift space distortion on scales as large 20 Mpc/h where we expect linear…

Astrophysics · Physics 2009-11-10 Biswajit Pandey , Somnath Bharadwaj

The power spectrum estimated from a galaxy redshift survey is the real spectrum convolved with a window function, so when estimating the power on very large scales (for small k), it is important that this window function be as narrow as…

Astrophysics · Physics 2009-10-07 Max Tegmark

The redshift-space bispectrum (three point statistics) of galaxies depends on the expansion rate, the growth rate, and geometry of the Universe, and hence can be used to measure key cosmological parameters. In a homogeneous Universe the…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Praful Gagrani , Lado Samushia

In this Letter we point out that redshift surveys can break the degeneracy between the galaxy bias, the power spectrum normalization, \sigma_{8,0} and the growth factor, without the need for external information by using a simple and rather…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Cinzia Di Porto , Luca Amendola , Enzo Branchini

The geometry of the Universe may be probed using the Alcock-Paczynski (AP) effect, in which the observed redshift size of a spherical distribution of sources relative to its angular size varies according to the assumed cosmological model.…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-10 Fulvio Melia , Jin Qin , Tong-Jie Zhang

The angular power spectrum is a gauge-independent observable that is in principle the natural tool for analysing galaxy number counts. In practice, the problem is that the computational requirements for next-generation spectroscopic surveys…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-12 Stefano Camera , José Fonseca , Roy Maartens , Mário G. Santos

Precision measurements of the galaxy power spectrum P(k) require a data analysis pipeline that is both fast enough to be computationally feasible and accurate enough to take full advantage of high-quality data. We present a rigorous…

Astrophysics · Physics 2009-10-07 Max Tegmark , Andrew Hamilton , Michael Strauss , Michael Vogeley , Alexander Szalay

The angular power spectrum C_l is extracted from the 4 year COBE DMR data with a 20 degree galactic cut, using the narrowest window functions possible. The average power in eight multipole bands is also computed, and plotted together with a…

Astrophysics · Physics 2009-10-28 Max Tegmark

We propose a new method for cosmological parameters extraction using the baryon acoustic oscillation scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-25 E. Sanchez , A. Carnero , J. Garcia-Bellido , E. Gaztanaga , F. de Simoni , M. Crocce , A. Cabre , P. Fosalba , D. Alonso

We investigate the cosmological dependence and the constraining power of large-scale galaxy correlations, including all redshift-distortions, wide-angle, lensing and gravitational potential effects on linear scales. We analyze the…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Alvise Raccanelli , Francesco Montanari , Daniele Bertacca , Olivier Doré , Ruth Durrer

We present measurements of the weak gravitational lensing shear power spectrum based on $450$ sq. deg. of imaging data from the Kilo Degree Survey. We employ a quadratic estimator in two and three redshift bins and extract band powers of…

We examine the effect of a threshold bias on the power spectrum and the bispectrum in an ensemble of numerical simulations (Gaussian initial perturbations with power law spectra P(k) \sim k^n, n=+1, 0, -1, -2) and compare our results with…

Astrophysics · Physics 2015-06-24 J. N. Fry , Adrian L. Melott , Sergei F. Shandarin

Cross-correlating the lensing signals of galaxies and comic microwave background (CMB) fluctuations is expected to provide valuable cosmological information. In particular it may help tighten constraints on parameters describing the…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-14 Philipp M. Merkel , Bjoern Malte Schaefer

We compute the angular power spectrum C_l from 1.5 million galaxies in early SDSS data on large angular scales, l<600. The data set covers about 160 square degrees, with a characteristic depth of order 1 Gpc/h in the faintest (21<r<22) of…

A new computational scheme for the nonlinear cosmological matter power spectrum (PS) is presented. Our method is based on evolution equations in time, which can be cast in a form extremely convenient for fast numerical evaluations. A…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Stefano Anselmi , Massimo Pietroni

In this paper, we develop a theory of redshift distortion of the galaxy power spectrum in the discrete wavelet transform (DWT) representation. Because the DWT power spectrum is dependent of both the scale and shape (configuration) of the…

Astrophysics · Physics 2009-11-07 Xiao-Hu Yang , Long-Long Feng , Yao-Quan Chu , Li-Zhi Fang

In this paper we examine magnitudes of quasars as a function of redshift in different frequency ranges (u,g,r,i,z). We show that on the smoothed curves mag(Z) in frequency ranges u,g,r there are characteristic features both similar for all…

General Physics · Physics 2012-12-27 Iurii Kudriavtcev

Weak lensing surveys are reaching sensitivities at which uncertainties in the galaxy redshift distributions n(z) from photo-z errors degrade cosmological constraints. We use ray-tracing simulations and a simple treatment of photo-z errors…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Matthew W. Abruzzo , Zoltán Haiman
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