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We study the sample variance of the matter power spectrum for the standard Lambda Cold Dark Matter universe. We use a total of 5000 cosmological N-body simulations to study in detail the distribution of best-fit cosmological parameters and…

Weak gravitational lensing observations probe the spectrum and evolution of density fluctuations and the cosmological parameters which govern them. At low redshifts, the non-linear gravitational evolution of large scale structure produces a…

Astrophysics · Physics 2009-10-31 Asantha Cooray , Wayne Hu

We investigate the information on cosmology contained in Gaussianised weak gravitational lensing convergence fields. Employing Box-Cox transformations to determine optimal transformations to Gaussianity, we develop analytical models for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 B. Joachimi , A. N. Taylor , A. Kiessling

We calculate the noise induced in the anisotropies of the astrophysical gravitational-wave background by finite sampling of both the galaxy distribution and the compact binary coalescence event rate. This shot noise leads to a…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-29 Alexander C. Jenkins , Mairi Sakellariadou

We compute the covariance of the galaxy power spectrum multipoles in perturbation theory, including the effects of nonlinear evolution, nonlinear and nonlocal bias, radial redshift-space distortions, arbitrary survey window and shot noise.…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Digvijay Wadekar , Roman Scoccimarro

Bounds for the correlation functions of identical bosons are discussed for the general case of a Gaussian density matrix. In particular, for a purely chaotic system the two-particle correlation function must always be greater than one. On…

High Energy Physics - Phenomenology · Physics 2009-10-22 M. Plümer , L. V. Razumov , R. M. Weiner

In the era of precision cosmology, establishing the correct magnitude of statistical errors in cosmological parameters is of crucial importance. However, widely used approximations in galaxy surveys analyses can lead to parameter…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Nicola Bellomo , José Luis Bernal , Giulio Scelfo , Alvise Raccanelli , Licia Verde

We investigate whether a Gaussian likelihood is sufficient to obtain accurate parameter constraints from a Euclid-like combined tomographic power spectrum analysis of weak lensing, galaxy clustering and their cross-correlation. Testing its…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 Robin E. Upham , Michael L. Brown , Lee Whittaker

It is well known that magnification bias, the modulation of galaxy or quasar source counts by gravitational lensing, can change the observed angular correlation function. We investigate magnification-induced changes to the shape of the…

Astrophysics · Physics 2008-12-18 Marilena LoVerde , Lam Hui , Enrique Gaztanaga

Shot noise is an important ingredient to any measurement or theoretical modeling of discrete tracers of the large scale structure. Recent work has shown that the shot noise in the halo power spectrum becomes increasingly sub-Poissonian at…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-21 Dimitry Ginzburg , Vincent Desjacques , Kwan Chuen Chan

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

The power spectrum, as a statistic in Fourier space, is commonly numerically calculated using the fast Fourier transform method to efficiently reduce the computational costs. To alleviate the systematic bias known as aliasing due to the…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Yipeng Wang , Yu Yu

We investigate the impact of different assumptions in the modeling of one-loop galaxy bias on the recovery of cosmological parameters, as a follow up of the analysis done in the first paper of the series at fixed cosmology. We use three…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-01 Andrea Pezzotta , Martin Crocce , Alexander Eggemeier , Ariel G. Sánchez , Román Scoccimarro

We derive an exact expression for the correlation function in redshift shells including all the relativistic contributions. This expression, which does not rely on the distant-observer or flat-sky approximation, is valid at all scales and…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Vittorio Tansella , Camille Bonvin , Ruth Durrer , Basundhara Ghosh , Elena Sellentin

It was recently shown that applying a Gaussianizing transform, such as a logarithm, to the nonlinear matter density field extends the range of useful applicability of the power spectrum by a factor of a few smaller. Such a transform…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-15 Mark C. Neyrinck

We present new results on the gravitational lensing shear and magnification power spectra obtained from numerical simulations of a flat cosmology with a cosmological constant. These results are of considerable interest since both the shear…

Astrophysics · Physics 2009-11-07 Andrew J. Barber , A. N. Taylor

Naive estimates of the statistics of large scale structure and weak lensing power spectrum measurements that include only Gaussian errors exaggerate their scientific impact. Non-linear evolution and finite volume effects are both…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-24 Emmanuel Schaan , Masahiro Takada , David N. Spergel

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

Distances in cosmology are usually inferred from observed redshifts - an estimate that is dependent on the local peculiar motion - giving a distorted view of the three dimensional structure and affecting basic observables such as the…

Astrophysics · Physics 2008-12-18 J. Richard Shaw , Antony Lewis

We find statistically significant correlations in the cosmological matter power spectrum over the full range of observable scales. While the correlations between individual modes are weak, the band-averaged power spectrum shows strong…

Astrophysics · Physics 2009-10-31 A. Meiksin , Martin White