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Julien Lesgourgues

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Related publications (71)

Page 2 of 4

Euclid: Validation of the MontePython forecasting tools

Maurizio Martinelli, Frédéric Courbin, Georges Meylan, Julien Lesgourgues, Slobodan Ilic

Context. The Euclid mission of the European Space Agency will perform a survey of weak lensing cosmic shear and galaxy clustering in order to constrain cosmological models and fundamental physics. Aims. We expand and adjust the mock Euclid likelihoods of t ...

Edp Sciences S A2024

Planck 2013 results. XIX. The integrated Sachs-Wolfe effect

Julien Lesgourgues, Slobodan Ilic

Based on cosmic microwave background (CMB) maps from the 2013 Planck Mission data release, this paper presents the detection of the integrated Sachs-Wolfe (ISW) effect, that is, the correlation between the CMB and large-scale evolving gravitational potenti ...

Edp Sciences S A2014

Cosmological constraints on deviations from Lorentz invariance in gravity and dark matter

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

We consider a scenario where local Lorentz invariance is violated by the existence of a preferred time direction at every space-time point. This scenario can arise in the context of quantum gravity and its description at low energies contains a unit time-l ...

Iop Publishing Ltd2015

Cosmological constraints on a light nonthermal sterile neutrino

Julien Lesgourgues

Although the MiniBooNE experiment has severely restricted the possible existence of light sterile neutrinos, a few anomalies persist in oscillation data, and the possibility of extra light species contributing as a subdominant hot (or warm) component is st ...

American Physical Society2009

Dark energy with non-adiabatic sound speed: initial conditions and detectability

Julien Lesgourgues

Assuming that the universe contains a dark energy fluid with a constant linear equation of state and a constant sound speed, we study the prospects of detecting dark energy perturbations using CMB data from Planck, cross-correlated with galaxy distribution ...

2010

The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths

Julien Lesgourgues

We present the Planck Sky Model (PSM), a parametric model for generating all-sky, few arcminute resolution maps of sky emission at submillimetre to centimetre wavelengths, in both intensity and polarisation. Several options are implemented to model the cos ...

Edp Sciences S A2013

Planck 2013 results. I. Overview of products and scientific results

Xin Chen, Julien Lesgourgues, Jason Douglas McEwen, Slobodan Ilic

The European Space Agency's Planck satellite, dedicated to studying the early Universe and its subsequent evolution, was launched 14 May 2009 and has been scanning the microwave and submillimetre sky continuously since 12 August 2009. In March 2013, ESA an ...

Edp Sciences S A2014

Planck 2013 results. XXXI. Consistency of the Planck data

Julien Lesgourgues

The Planck design and scanning strategy provide many levels of redundancy that can be exploited to provide tests of internal consistency. One of the most important is the comparison of the 70 GHz (amplifier) and 100 GHz (bolometer) channels. Based on diffe ...

Edp Sciences S A2014

Planck 2013 results. XII. Diffuse component separation

Xin Chen, Julien Lesgourgues

Planck has produced detailed all-sky observations over nine frequency bands between 30 and 857 GHz. These observations allow robust reconstruction of the primordial cosmic microwave background (CMB) temperature fluctuations over nearly the full sky, as wel ...

Edp Sciences S A2014

Planck 2013 results. II. Low Frequency Instrument data processing

Xin Chen, Julien Lesgourgues

We describe the data processing pipeline of the Planck Low Frequency Instrument (LFI) data processing centre (DPC) to create and characterize full-sky maps based on the first 15.5 months of operations at 30, 44, and 70 GHz. In particular, we discuss the va ...

Edp Sciences S A2014

HFI energetic particle effects: characterization, removal, and simulation

Julien Lesgourgues

We describe the detection, interpretation, and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). There are two types of interactions: heating of the 0.1 K bolometer plate; and glitch ...

Edp Sciences S A2014

The effective gravitational decoupling between dark matter and the CMB

Julien Lesgourgues

We present a detailed and self-contained analytical derivation of the evolution of sub-horizon cosmological perturbations before decoupling, based on previous work by S. Weinberg. These solutions are valid in the minimal Lambda CDM scenario, to first order ...

Iop Publishing Ltd2014

Planck 2013 results. XVII. Gravitational lensing by large-scale structure

Julien Lesgourgues

On the arcminute angular scales probed by Planck, the cosmic microwave background (CMB) anisotropies are gently perturbed by gravitational lensing. Here we present a detailed study of this effect, detecting lensing independently in the 100, 143, and 217 GH ...

Edp Sciences S A2014

High Frequency Instrument data processing

Xin Chen, Julien Lesgourgues

We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the s ...

Edp Sciences S A2014

Planck 2013 results. XI. All-sky model of thermal dust emission

Julien Lesgourgues

This paper presents an all-sky model of dust emission from the Planck 353, 545, and 857 GHz, and IRAS 100 mu m data. Using a modified blackbody fit to the data we present all-sky maps of the dust optical depth, temperature, and spectral index over the 353- ...

Edp Sciences S A2014

Planck 2013 results. XXII. Constraints on inflation

Julien Lesgourgues

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

The Cosmic Linear Anisotropy Solving System (CLASS). Part II: Approximation schemes

Julien Lesgourgues, Diego Blas Temino

Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires from 104 to 105 Bo ...

2011

Cosmological parameters from large scale structure - geometric versus shape information

Julien Lesgourgues

The matter power spectrum as derived from large scale structure (LSS) surveys contains two important and distinct pieces of information: an overall smooth shape and the imprint of baryon acoustic oscillations (BAO). We investigate the separate impact of th ...

2010

Planck 2013 results. XXVIII. The Planck Catalogue of Compact Sources

Xin Chen, Julien Lesgourgues, Benjamin Andreas Walter

The Planck Catalogue of Compact Sources (PCCS) is the catalogue of sources detected in the first 15 months of Planck operations, the "nominal" mission. It consists of nine single-frequency catalogues of compact sources, both Galactic and extragalactic, det ...

Edp Sciences S A2014

Neutrino masses and cosmological parameters from a Euclid-like survey: Markov Chain Monte Carlo forecasts including theoretical errors

Julien Lesgourgues, Benjamin Audren

We present forecasts for the accuracy of determining the parameters of a minimal cosmological model and the total neutrino mass based on combined mock data for a future Euclid-like galaxy survey and Planck. We consider two different galaxy surveys: a spect ...

Iop Publishing Ltd2013