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Julien Lesgourgues

Cette personne a quitté l’EPFL

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Publications associées (71)

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Probing nuclear rates with Planck and BICEP2

Julien Lesgourgues

Big-bang nucleosynthesis (BBN) relates key cosmological parameters to the primordial abundance of light elements. In this paper, we point out that the recent observations of cosmic microwave background anisotropies by the Planck satellite and by the BICEP2 ...

American Physical Society2014

Using the CMB angular power spectrum to study Dark Matter-photon interactions

Julien Lesgourgues

In this paper, we explore the impact of Dark Matter-photon interactions on the CMB angular power spectrum. Using the one-year data release of the Planck satellite, we derive an upper bound on the Dark Matter-photon elastic scattering cross section of sigma ...

Iop Publishing Ltd2014

Perturbation Theory Of The Cosmological Log-Density Field

Julien Lesgourgues

The matter density field exhibits a nearly lognormal probability density distribution after entering into the nonlinear regime. Recently, it has been shown that the shape of the power spectrum of a logarithmically transformed density field is very close to ...

2011

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

Julien Lesgourgues, Jason Douglas McEwen

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

Planck 2013 results. XXXII. The updated Planck catalogue of Sunyaev-Zeldovich sources

Xin Chen, Julien Lesgourgues

We update the all-sky Planck catalogue of 1227 clusters and cluster candidates (PSZ1) published in March 2013, derived from detections of the Sunyaev-Zeldovich (SZ) effect using the first 15.5 months of Planck satellite observations. As an addendum, we del ...

Edp Sciences S A2015

Cosmological parameter estimation with large scale structure observations

Julien Lesgourgues

We estimate the sensitivity of future galaxy surveys to cosmological parameters, using the redshift dependent angular power spectra of galaxy number counts, C-l(z(1), z(2)), calculated with all relativistic corrections at first order in perturbation theory ...

Iop Publishing Ltd2014

Lyman-alpha constraints on warm and on warm-plus-cold dark matter models

Julien Lesgourgues, Alexey Boyarsky, Oleg Ruchayskiy

We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up which is a good approximation for several theoretically wel ...

2008

Planck 2013 results. XXIX. The Planck catalogue of Sunyaev-Zeldovich sources

Xin Chen, Julien Lesgourgues

We describe the all-sky Planck catalogue of clusters and cluster candidates derived from Sunyaev-Zeldovich (SZ) effect detections using the first 15.5 months of Planck satellite observations. The catalogue contains 1227 entries, making it over six times th ...

Edp Sciences S A2014

Cosmological constraints on Lorentz violating dark energy

Julien Lesgourgues, Sergey Sibiryakov, Diego Blas Temino, Benjamin Audren

The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the c ...

Iop Publishing Ltd2013

Robustness of cosmic neutrino background detection in the cosmic microwave background

Julien Lesgourgues, Benjamin Audren

The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming spe ...

Iop Publishing Ltd2015

Strongest model-independent bound on the lifetime of Dark Matter

Julien Lesgourgues, Benjamin Audren

Dark Matter is essential for structured formation in the late Universe so it must be stable on cosmological time scales. But how stable exactly? Only assuming decays into relativistic on particles, we report an otherwise model independent bound on the life ...

Iop Publishing Ltd2014

Planck intermediate results XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

Julien Lesgourgues

The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI po ...

EDP Sciences2016

Cosmological lepton asymmetry with a nonzero mixing angle theta(13)

Julien Lesgourgues

While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries using some of t ...

American Physical Society2012

The Cosmic Linear Anisotropy Solving System (CLASS) IV: efficient implementation of non-cold relics

Julien Lesgourgues

We present a new flexible, fast and accurate way to implement massive neutrinos, warm dark matter and any other non-cold dark matter relics in Boltzmann codes. For whatever analytical or numerical form of the phase-space distribution function, the optimal ...

2011

Constraint on neutrino masses from SDSS-III/BOSS Ly alpha forest and other cosmological probes

Julien Lesgourgues

We present constraints on the parameters of the ACDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly alpha forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky ...

Iop Publishing Ltd2015

Neutrino cosmology and Planck

Julien Lesgourgues

Relic neutrinos play an important role in the evolution of the Universe, modifying some of the cosmological observables. We summarize the main aspects of cosmological neutrinos and describe how the precision of present cosmological data can be used to lear ...

Iop Publishing Ltd2014

Planck 2013 results. XIII. Galactic CO emission

Xin Chen, Julien Lesgourgues

Rotational transition lines of CO play a major role in molecular radio astronomy as a mass tracer and in particular in the study of star formation and Galactic structure. Although a wealth of data exists for the Galactic plane and some well-known molecular ...

Edp Sciences S A2014

REVIEW OF PARTICLE PHYSICS Particle Data Group

Maroussia Schaffner Portillo, Juan Diego Gomez Valencia, Olivier Schneider, Christophe Bauer, Greig Alan Cowan, Julien Lesgourgues, Varun Sharma, Riddhiman Sarkar, Florian Patrick Marie Daniel De la Barre De Nanteuil, Kai Oliver Arras, Lorena Gonçalves de Alcântara e Freitas Krikler, Maria Rosaria Antonelli

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements from 758 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, lepton ...

American Physical Society2018

Constraining dark matter-neutrino interactions using the CMB and large-scale structure

Julien Lesgourgues

We present a new study on the elastic scattering cross section of dark matter (DM) and neutrinos using the latest cosmological data from Planck and large-scale structure experiments. We find that the strongest constraints are set by the Lyman-a forest, giv ...

Iop Publishing Ltd2014

Zodiacal emission

Xin Chen, Julien Lesgourgues

The Planck satellite provides a set of all-sky maps at nine frequencies from 30 GHz to 857 GHz. Planets, minor bodies, and di ff use interplanetary dust emission (IPD) are all observed. The IPD can be separated from Galactic and other emissions because Pla ...

Edp Sciences S A2014