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Concept

Équations de Friedmann

Publications associées (32)

Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies

Frédéric Courbin, Julien Lesgourgues, Mikhail Ivanov, Richard Irving Anderson

The standard Lambda Cold Dark Matter (Lambda CDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to ...

ELSEVIER2022

Euclid preparation: XI. Mean redshift determination from galaxy redshift probabilities for cosmic shear tomography

Yi Wang, Gianluca Castignani

The analysis of weak gravitational lensing in wide-field imaging surveys is considered to be a major cosmological probe of dark energy. Our capacity to constrain the dark energy equation of state relies on an accurate knowledge of the galaxy mean redshift ...

2021

Time delay lens modelling challenge

Frédéric Courbin, Vivien François Bonvin, Martin Raoul Robert Millon, Aymeric Alexandre Galan

In recent years, breakthroughs in methods and data have enabled gravitational time delays to emerge as a very powerful tool to measure the Hubble constant H-0. However, published state-of-the-art analyses require of order 1 yr of expert investigator time a ...

OXFORD UNIV PRESS2021

Euclid : Effects of sample covariance on the number counts of galaxy clusters

Yi Wang, Georges Meylan

Aims. We investigate the contribution of shot-noise and sample variance to uncertainties in the cosmological parameter constraints inferred from cluster number counts, in the context of the Euclid survey. ...

EDP SCIENCES S A2021

Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data

Eduardo Sanchez, Jonathan Andrew Blazek

We study a phenomenological class of models where dark matter converts to dark radiation in the low redshift epoch. This class of models, dubbed DMDR, characterizes the evolution of comoving dark-matter density with two extra parameters, and may be able to ...

American Physical Society2021

Testing general relativity on cosmological scales at redshift z similar to 1.5 with quasar and CMB lensing

Cheng Zhao

We test general relativity (GR) at the effective redshift (z) over tilde similar to 1.5 by estimating the statistic E-G, a probe of gravity, on cosmological scales 19 - 190 h(-1)Mpc. This is the highest redshift and largest scale estimation of E-G so far. ...

OXFORD UNIV PRESS2021

Reducing the variance of redshift space distortion measurements from mock galaxy catalogues with different lines of sight

Cheng Zhao

Accuratemock catalogues are essential for assessing systematics in the cosmological analysis of large galaxy surveys. Anisotropic two-point clustering measurements from the same simulation show some scatter for different lines of sight (LOS), but are on av ...

OXFORD UNIV PRESS2021

On the stability of blowup solutions for the critical corotational wave-map problem

Joachim Krieger, Shuang Miao

We show that the finite time blow up solutions for the co-rotational Wave Maps problem constructed in [7,15] are stable under suitably small perturbations within the co-rotational class, provided the scaling parameter

λ(t)=t−1−ν

is sufficiently close to ...

2020

Euclid preparation: VII. Forecast validation for Euclid cosmological probes

Yi Wang, Maurizio Martinelli, Georges Meylan, Murat Kunt, Slobodan Ilic

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

Probing the gravitational wave background from cosmic strings with LISA

Daniel Garcia Figueroa

Cosmic string networks offer one of the best prospects for detection of cosmological gravitational waves (GWs). The combined incoherent GW emission of a large number of string loops leads to a stochastic GW background (SGWB), which encodes the properties o ...

2020

Backreaction of electromagnetic fields and the Schwinger effect in pseudoscalar inflation magnetogenesis

Oleksandr Sobol

We study magnetogenesis in axionlike inflation driven by a pseudoscalar field phi coupled axially to the electromagnetic (EM) field (beta/M-p)phi F-mu nu(F) over tilde mu nu with dimensionless coupling constant beta. A set of equations for the inflaton fie ...

American Physical Society2019

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

Publications associées (32)

Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies

Frédéric Courbin, Julien Lesgourgues, Mikhail Ivanov, Richard Irving Anderson

ELSEVIER2022

Reducing the variance of redshift space distortion measurements from mock galaxy catalogues with different lines of sight

Cheng Zhao

OXFORD UNIV PRESS2021

On the stability of blowup solutions for the critical corotational wave-map problem

Joachim Krieger, Shuang Miao

λ(t)=t−1−ν

is sufficiently close to ...

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

OXFORD UNIV PRESS2020