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Concept

Cosmologie inhomogène

Publications associées (31)

Effective photon mass and (dark) photon conversion in the inhomogeneous Universe

Kyrylo Bondarenko

Photons traveling cosmological distances through the inhomogeneous Universe experience a great variation in their in-medium induced effective mass. Using the EAGLE suite of hydrodynamical simulations, we infer the free electron distribution and thereby the ...

IOP PUBLISHING LTD2020

Constraining dark photons and their connection to 21 cm cosmology with CMB data

Kyrylo Bondarenko

In the inhomogeneous Universe, the cosmological conversion of dark photons into ordinary photons (and vice versa) may happen at a great number of resonance redshifts. This alters the CMB observed energy spectrum and degree of small-scale anisotropies. We u ...

2020

H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H-0

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin

We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 - 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obtained by the COSm ...

OXFORD UNIV PRESS2020

Very massive tracers and higher derivative biases

Valentin Mauerhofer

Most of the upcoming cosmological information will come from analyzing the clustering of the Large Scale Structures (LSS) of the universe through LSS or CMB observations. It is therefore essential to be able to understand their behavior with exquisite prec ...

2020

H0LiCOW-XIII. A 2.4 per cent measurement of H-0 from lensed quasars: 5.3 sigma tension between early- and late-Universe probes

Frédéric Courbin, Georges Meylan, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon, Olga Tihhonova

We present a measurement of the Hubble constant (H-0) and other cosmological parameters from a joint analysis of six gravitationally lensed quasars with measured time delays. All lenses except the first are analysed blindly with respect to the cosmological ...

OXFORD UNIV PRESS2020

Non-perturbative probability distribution function for cosmological counts in cells

Sergey Sibiryakov, Mikhail Ivanov

We present a non-perturbative calculation of the 1-point probability distribution function (PDF) for the spherically-averaged matter density field. The PDF is represented as a path integral and is evaluated using the saddle-point method. It factorizes into ...

IOP PUBLISHING LTD2019

Precision theoretical methods for large-scale structure of the Universe

Mikhail Ivanov

We develop new analytic methods to accurately describe the formation of cosmic large-scale structure. These methods are based on the path integral formalism and allows one to efficiently address a number of long-standing problems in the field. We describe ...

EPFL2019

DeepSphere: Efficient spherical convolutional neural network with HEALPix sampling for cosmological applications

Nathanaël Perraudin, Michaël Defferrard

Convolutional Neural Networks (CNNs) are a cornerstone of the Deep Learning toolbox and have led to many breakthroughs in Artificial Intelligence. So far, these neural networks (NNs) have mostly been developed for regular Euclidean domains such as those su ...

ELSEVIER SCIENCE BV2019

Dark Energy Survey Year 1 Results: Tomographic cross-correlations between Dark Energy Survey galaxies and CMB lensing from South Pole Telescope plus Planck

Eduardo Sanchez, Jonathan Andrew Blazek

We measure the cross-correlation between REDMAGIC galaxies selected from the Dark Energy Survey (DES) year 1 data and gravitational lensing of the cosmic microwave background (CMB) reconstructed from South Pole Telescope (SPT) and Planck data over 1289 deg ...

American Physical Society2019

DES Y1 Results: validating cosmological parameter estimation using simulated Dark Energy Surveys

Mingkui Wang, Eduardo Sanchez, Craig Matthew Smith, Jonathan Andrew Blazek, Augusto Martins Lima

We use mock galaxy survey simulations designed to resemble the Dark Energy Survey Year 1 (DES Y1) data to validate and inform cosmological parameter estimation. When similar analysis tools are applied to both simulations and real survey data, they provide ...

OXFORD UNIV PRESS2018

Advanced gravitational lensing techniques for precision cosmology

Markus Rexroth

Gravitational lensing - the deflection of light by gravity - has greatly developed since its famous first observation in 1919, which validated Einstein's General Theory of Relativity. The strength of this effect does not depend on the nature of the mass wh ...

EPFL2018