Publications associées à Cosmologie bouddhiste

Heuristic Estimation of the Vacuum Energy Density of the Universe: Part I—Analysis Based on Time Domain Electromagnetic Radiation

In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant ...

2023

Examining the relationship between the bulge-to-total stellar mass ratio and dwarf galaxy count in the context of ΛCDM

Oliver Müller

Previous results suggest that there is a correlation between the size of the bulge of a galaxy and the number of its dwarf galaxy satellites. This was found to be inconsistent with the standard model of cosmology based on comparisons to semi-analytical dar ...

Edp Sciences S A2023

The DESI N-body Simulation Project - II. Suppressing sample variance with fast simulations

Andrei Variu, Cheng Zhao, Yu Yu, Hanyu Zhang

Dark Energy Spectroscopic Instrument (DESI) will construct a large and precise three-dimensional map of our Universe. The survey effective volume reaches similar to 20 h(-3) Gpc(3). It is a great challenge to prepare high-resolution simulations with a much ...

OXFORD UNIV PRESS2022

Assessing tension metrics with dark energy survey and Planck data

Eduardo Sanchez, Jonathan Andrew Blazek

Quantifying tensions - inconsistencies amongst measurements of cosmological parameters by different experiments - has emerged as a crucial part of modern cosmological data analysis. Statistically significant tensions between two experiments or cosmological ...

2021

The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Large-scale structure catalogues for cosmological analysis

Jean-Paul Richard Kneib, Cheng Zhao, Johan Comparat, Anand Stéphane Raichoor

We present large-scale structure catalogues from the completed extended Baryon Oscillation Spectroscopic Survey (eBOSS). Derived from Sloan Digital Sky Survey (SDSS) IV Data Release 16 (DR16), these catalogues provide the data samples, corrected for observ ...

OXFORD UNIV PRESS2020

Euclid preparation: VII. Forecast validation for Euclid cosmological probes

Murat Kunt, Georges Meylan, Jean-Luc Starck, Slobodan Ilic, Maurizio Martinelli, Yi Wang, Richard Massey

Aims. The Euclid space telescope will measure the shapes and redshifts of galaxies to reconstruct the expansion history of the Universe and the growth of cosmic structures. The estimation of the expected performance of the experiment, in terms of predicted ...

EDP SCIENCES SA2020

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

Precise measurements of time delays in gravitationally lensed quasars for competitive and independent determination of the Hubble constant

Vivien François Bonvin

During these last decades, by virtue of observations, the Standard Cosmological Model has emerged, providing a description of the Universe's evolution using a minimal set of independent constraints - the cosmological parameters. Among them is the expansion ...

EPFL2017

A 24 mm diameter fibre positioner for spectroscopic surveys

Hannes Bleuler, Mohamed Bouri, Jean-Paul Richard Kneib, Luzius Gregor Kronig, Philipp Hörler

One of the big research topics in modern cosmology is the mystery of dark Energy. To unveil the secret, cosmologists want to measure precisely the evolution of large scale structures in the universe. One way of doing so is to measure the 3D location of a h ...

Spie-Int Soc Optical Engineering2016

Poincaré, Scale and Conformal Symmetries : Gauge Perspective and Cosmological Ramifications

Georgios Karananas

Symmetries are omnipresent and play a fundamental role in the description of Nature. Thanks to them, we have at our disposal nontrivial selection rules that dictate how a theory should be constructed. This thesis, which is naturally divided into two parts, ...

EPFL2016

The Weak Lensing Signal And The Clustering Of Boss Galaxies. I. Measurements

Jean-Paul Richard Kneib

A joint analysis of the clustering of galaxies and their weak gravitational lensing signal is well-suited to simultaneously constrain the galaxy-halo connection as well as the cosmological parameters by breaking the degeneracy between galaxy bias and the a ...

American Astronomical Society2015

Cosmology From Gravitational Lens Time Delays And Planck Data

Frédéric Courbin, Georges Meylan, Malte Tewes

Under the assumption of a flat Lambda CDM cosmology, recent data from the Planck satellite point toward a Hubble constant that is in tension with that measured by gravitational lens time delays and by the local distance ladder. Prosaically, this difference ...

Iop Publishing Ltd2014

Separate constraints on early and late cosmology

Benjamin Audren

Since the public release of Planck data, several attempts have been made to explain the observed small tensions with other data sets, most of them involving an extension of the Lambda cold dark matter (Lambda CDM) model. We try here an alternative approach ...

Oxford Univ Press2014

Image Analysis For Cosmology: Results From The Great10 Star Challenge

Frédéric Courbin, Georges Meylan, Marc Gentile, Richard Massey

We present the results from the first public blind point-spread function (PSF) reconstruction challenge, the GRavitational lEnsing Accuracy Testing 2010 (GREAT10) Star Challenge. Reconstruction of a spatially varying PSF, sparsely sampled by stars, at non- ...

University of Chicago Press2013

Sparsity and the Bayesian perspective

Anaïs Marie Rassat, Jean-Luc Starck

Sparsity has recently been introduced in cosmology for weak-lensing and cosmic microwave background (CMB) data analysis for different applications such as denoising, component separation, or inpainting (i.e., filling the missing data or the mask). Although ...

Edp Sciences S A2013

Weak Gravitational Lensing by Large-Scale Structures : A Tool for Constraining Cosmology

Marc Gentile

There is now very strong evidence that our Universe is undergoing an accelerated expansion period as if it were under the influence of a gravitationally repulsive “dark energy” component. Furthermore, most of the mass of the Universe seems to be in the for ...

EPFL2013

Conservative constraints on early cosmology with MONTE PYTHON

Julien Lesgourgues, Benjamin Audren

Models for the latest stages of the cosmological evolution rely on a less solid theoretical and observational ground than the description of earlier stages like BBN and recombination. As suggested in a previous work by Vonlanthen et al., it is possible to ...

Iop Publishing Ltd2013

Image analysis for cosmology: results from the GREAT10 Galaxy Challenge

Frédéric Courbin, Malte Tewes, Marc Gentile, Nicolas Cantale, Guldariya Nurbaeva, Richard Massey

In this paper, we present results from the weak-lensing shape measurement GRavitational lEnsing Accuracy Testing 2010 (GREAT10) Galaxy Challenge. This marks an order of magnitude step change in the level of scrutiny employed in weak-lensing shape measureme ...

Blackwell Publishing Ltd, Oxford2012

Acoustic resonant sensor for ultra high energy neutrino detection

Mathieu Ribordy, Reto Frei

The characterization of the cosmogenic neutrino flux would give insights into cosmological source evolution, source spectra and composition at injection, through the partial recovery of the degraded information carried by the ultra high energy cosmic rays. ...

2011