Publications associées à Corde cosmique

Stochastic gravitational-wave background from metastable cosmic strings

A metastable cosmic-string network is a generic consequence of many grand unified theories (GUTs) when combined with cosmic inflation. Metastable cosmic strings are not topologically stable, but decay on cosmic time scales due to pair production of GUT mon ...

IOP Publishing Ltd2021

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

From NANOGrav to LIGO with metastable cosmic strings

Valerie Fiona Domcke

We interpret the recent NANOGrav results in terms of a stochastic gravitational wave background from metastable cosmic strings. The observed amplitude of a stochastic signal can be translated into a range for the cosmic string tension and the mass of magne ...

2020

COSMOGRAIL XVIII. time delays of the quadruply lensed quasar WFI2033-4723

Frédéric Courbin, Georges Meylan, Malte Tewes, Sun Hee Kim, Vivien François Bonvin, Hung-Hsu Chan, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate

We present new measurements of the time delays of WFI2033-4723. The data sets used in this work include 14 years of data taken at the 1.2 m Leonhard Euler Swiss telescope, 13 years of data from the SMARTS 1.3 m telescope at Las Campanas Observatory and a s ...

2019

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

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

Inconsistency of an inflationary sector coupled only to Einstein gravity

Daniel Garcia Figueroa

From a model-building perspective, the inflationary sector might very well have no direct couplings to other species, apart from inevitable gravitational interactions. Within the context of General Relativity, a thermal universe can still emerge after infl ...

IOP PUBLISHING LTD2019

Impact of the 3D source geometry on time-delay measurements of lensed type-Ia supernovae

Frédéric Courbin, Vivien François Bonvin, Hung-Hsu Chan, Martin Raoul Robert Millon, Olga Tihhonova, Elodie Marie Charlène Savary

It has recently been proposed that gravitationally lensed type-Ia supernovae can provide microlensing-free time-delay measurements provided that the measurement is taken during the achromatic expansion phase of the explosion and that color light curves are ...

EDP SCIENCES S A2019

CFHTLenS: weak lensing calibrated scaling relations for low-mass clusters of galaxies

Jean-Paul Richard Kneib

L(X)We present weak lensing and X-ray analysis of 12 low-mass clusters from the Canada-France-Hawaii Telescope Lensing Survey and XMM-CFHTLS surveys. We combine these systems with high-mass systems from Canadian Cluster Comparison Project and low-mass syst ...

Oxford University Press2015

Planck 2013 results. XXV. Searches for cosmic strings and other topological defects

Julien Lesgourgues, Jason Douglas McEwen, Fabio Finelli

Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzm ...

Edp Sciences S A2014

How Self-Interactions can Reconcile Sterile Neutrinos with Cosmology

Short baseline neutrino oscillation experiments have shown hints of the existence of additional sterile neutrinos in the eV mass range. However, such neutrinos seem incompatible with cosmology because they have too large of an impact on cosmic structure fo ...

Amer Physical Soc2014

Effects of cosmic strings with delayed scaling on CMB anisotropy

Kohei Kamada

The network of cosmic strings generated in a phase transition during inflation enters the scaling regime later than that of usual strings. If it occurs after the recombination, temperature anisotropies of the cosmic microwave background (CMB) at high multi ...

American Physical Society2014

Constraints on primordial non-Gaussianity

Julien Lesgourgues, Fabio Finelli

The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent value ...

Edp Sciences S A2014

Planck 2013 results. XXII. Constraints on inflation

Julien Lesgourgues, Jean-Luc Starck, Fabio Finelli, Jan Hamann

We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be n(s) = 0.9603 +/- 0:0073, ruling ...

EDP Sciences2014

Ubiquity of non-diffusive momentum transport in JET H-modes

Henri Weisen, Yann Camenen, Mikhail Maslov

A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the ...

Int Atomic Energy Agency2012

A Framework for Numerical Simulations of Structure Formation

Claude Becker

In the absence of a full analytical treatment of nonlinear structure formation in the universe, numerical simulations provide the critical link between the properties of the underlying model and the features of the observed structures. Currently N-body sim ...

EPFL2011

Sequestering by global symmetries in Calabi–Yau string models

Claudio Scrucca, Christopher John Andrey

We study the possibility of realizing an effective sequestering between visible and hidden sectors in generic heterotic string models, generalizing previous work on orbifold constructions to smooth Calabi-Yau compactifications. In these theories, genuine s ...

Elsevier2011

Compressed sensing reconstruction of a string signal from interferometric observations of the cosmic microwave background

Pierre Vandergheynst, Yves Wiaux, Gilles Puy

We propose an algorithm for the reconstruction of the signal induced by cosmic strings in the cosmic microwave background (CMB), from radio-interferometric data at arcminute resolution. Radio interferometry provides incomplete and noisy Fourier measurement ...

Wiley-Blackwell2010

Compressed sensing imaging techniques for radio interferometry

Pierre Vandergheynst, Yves Wiaux, Gilles Puy, Laurent Jacques

Radio interferometry probes astrophysical signals through incomplete and noisy Fourier measurements. The theory of compressed sensing demonstrates that such measurements may actually suffice for accurate reconstruction of sparse or compressible signals. We ...

Wiley-Blackwell2009

Wavelet domain Bayesian denoising of string signal in the cosmic microwave background

Pierre Vandergheynst, Yves Wiaux

An algorithm is proposed for denoising the signal induced by cosmic strings in the cosmic microwave background (CMB). A Bayesian approach is taken, based on modeling the string signal in the wavelet domain with generalized Gaussian distributions. Good perf ...

2009