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We present a numerical technique to compute the gravitational lensing induced by simulated haloes. It relies on a 2D-Tree domain decomposition in the lens plane combined with a description of N-Body particles as extended clouds with a…

Astrophysics · Physics 2008-11-26 Dominique Aubert , Adam Amara , R. Benton Metcalf

A cosmic shear survey, spanning a significant proportion of the sky, should greatly improve constraints on a number of cosmological parameters. It also provides a unique opportunity to examine the matter power spectrum directly. However,…

Astrophysics · Physics 2009-11-13 Fergus Simpson

In this paper, we propose a new horseshoe-type prior hierarchy for adaptively shrinking spline-based functional effects towards a predefined vector space of parametric functions. Instead of shrinking each spline coefficient towards zero, we…

Methodology · Statistics 2021-01-15 Paul Wiemann , Thomas Kneib

We present a method to recover the shape and amplitude of the power spectrum of mass fluctuations, P(k), from observations of the high redshift \lya forest. The method is motivated by the physical picture of the \lya forest that has emerged…

Astrophysics · Physics 2009-10-30 Rupert A. C. Croft , David H. Weinberg , Neal Katz , Lars Hernquist

This paper introduces a new shape-based image reconstruction technique applicable to a large class of imaging problems formulated in a variational sense. Given a collection of shape priors (a shape dictionary), we define our problem as…

Functional Analysis · Mathematics 2013-03-04 Alireza Aghasi , Justin Romberg

In this paper we investigate power spectrum of a smoothed scalar field. The smoothing leads to the regularisation of the UV divergences and can be related with the internal structure of the considered field or the space itself. We apply…

High Energy Physics - Theory · Physics 2015-05-14 Jakub Mielczarek , Michal Kamionka

In this work we present a nonparametric approach, which works on minimal assumptions, to reconstruct the cosmic expansion of the Universe. We propose to combine a locally weighted scatterplot smoothing method and a simulation-extrapolation…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-20 Ariadna Montiel , Ruth Lazkoz , Irene Sendra , Celia Escamilla-Rivera , Vincenzo Salzano

We compute the power spectrum at one-loop order in standard perturbation theory for the matter density field to which a standard Lagrangian Baryonic acoustic oscillation (BAO) reconstruction technique is applied. The BAO reconstruction…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Chiaki Hikage , Kazuya Koyama , Alan Heavens

This paper investigates the shape reconstructions of sub-wavelength objects from near-field measurements in transverse electromagnetic scattering. This geometric inverse problem is notoriously ill-posed and challenging. We develop a novel…

Mathematical Physics · Physics 2023-05-03 M. H. Ding , H. Y. Liu , G. H. Zheng

We propose a novel bias-free method for reconstructing the power spectrum of the weak lensing deflection field from cosmic microwave background (CMB) observations. The proposed method is in contrast to the standard method of CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-30 Blake D. Sherwin , Sudeep Das

An obstacle to the detection of redshifted 21cm emission from the epoch of reionization (EoR) is the presence of foregrounds which exceed the cosmological signal in intensity by orders of magnitude. We argue that in principle it would be…

It has been shown that the large--scale correlation functions of the density field (and velocity divergence field) follow a specific hierarchy in the quasilinear regime and for Gaussian initial conditions (Bernardeau 1992). The exact…

Astrophysics · Physics 2007-05-23 F. Bernardeau

$ $Future surveys could obtain tighter constraints on the cosmological parameters with the galaxy power spectrum than with the Cosmic Microwave Background. However, the inclusion of multiple overlapping tracers, redshift bins, and more…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Yan Lai , Cullan Howlett , Tamara M. Davis

We find that nonlinearities in the dark-matter power spectrum are dramatically smaller if the density field first undergoes a logarithmic mapping. In the Millennium simulation, this procedure produces a power spectrum with a shape hardly…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Mark C. Neyrinck , István Szapudi , Alexander S. Szalay

We use multi-frequency information in first year WMAP data to search for the Sunyaev-Zeldovich (SZ) effect. WMAP has sufficiently broad frequency coverage to constrain SZ without the addition of higher frequency data: the SZ power spectrum…

Astrophysics · Physics 2009-11-10 Kevin M. Huffenberger , Uros Seljak , Alexey Makarov

Natural images tend to mostly consist of smooth regions with individual pixels having highly correlated spectra. This information can be exploited to recover hyperspectral images of natural scenes from their incomplete and noisy…

Computer Vision and Pattern Recognition · Computer Science 2016-11-03 Reza Arablouei , Frank de Hoog

A new technique of Fourier analysis on a cut sky (Gorski, 1994) has been applied to the two year COBE DMR sky maps. The Bayesian power spectrum estimation results are consistent with the Harrison-Zel'dovich n=1 model. The maximum likelihood…

Astrophysics · Physics 2009-06-16 K. M. Gorski , G. Hinshaw , A. J. Banday , C. L. Bennett , E. L. Wright , A. Kogut , G. F. Smoot , P. Lubin

We modify the public PM code developed by Anatoly Klypin and Jon Holtzman to simulate cosmology with arbitrary initial power spectrum and equation of state of dark energy. With this tool in hand, we perform the following studies on the…

Astrophysics · Physics 2011-02-11 Zhaoming Ma

In this article we give an account of a method of smoothing spatial inhomogeneous data sets by using wavelet reconstruction on a regular grid in an auxilliary space onto which the original data is mapped. In a previous paper by the present…

Astrophysics · Physics 2009-10-28 S. Rauzy , M. Lachièze-Rey , R. N. Henriksen