Model independent constraints on mass-varying neutrino scenarios (2009)
Franca, Urbano, Lattanzi, Massimiliano, Lesgourgues, Julien, Pastor, Sergio
Models of dark energy in which neutrinos interact with the scalar field supposed to be responsible for the acceleration of the universe usually imply a variation of the neutrino masses on...
Observing the Evolution of the Universe (2009)
Aguirre, James, Amblard, Alexandre, Ashoorioon, Amjad, Baccigalupi, Carlo, Balbi, Amedeo, Bartlett, James, ...
How did the universe evolve? The fine angular scale (l>1000) temperature and polarization anisotropies in the CMB are a Rosetta stone for understanding the evolution of the universe. Through detailed...
Optimising Boltzmann codes for the Planck era (2009)
Hamann, Jan, Balbi, Amedeo, Lesgourgues, Julien, Quercellini, Claudia
High precision measurements of the Cosmic Microwave Background (CMB) anisotropies, as can be expected from the Planck satellite, will require high-accuracy theoretical predictions as well. One...
Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
Previous fits of sterile neutrino dark matter models to cosmological data assumed a peculiar production mechanism, which is not representative of the best-motivated particle physics models given...
Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
Previous fits of sterile neutrino dark matter models to cosmological data assumed a peculiar production mechanism, which is not representative of the best-motivated particle physics models given...
Cosmological constraints on a light non-thermal sterile neutrino (2008)
Acero, Mario A., Lesgourgues, Julien
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...
Lyman-$\alpha$ constraints on warm and on warm-plus-cold dark matter models (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
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...
Lyman-alpha constraints on warm and on warm-plus-cold dark matter models (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
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...
CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)
Baumann, Daniel, Jackson, Mark G, Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...
CMBPol Mission Concept Study: Probing Inflation with CMB Polarization (2008)
Baumann, Daniel, Jackson, Mark G., Adshead, Peter, Amblard, Alexandre, Ashoorioon, Amjad, Bartolo, Nicola, ...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to...
How to constrain inflationary parameter space with minimal priors (2008)
Hamann, Jan, Lesgourgues, Julien, Valkenburg, Wessel
We update constraints on the Hubble function H(phi) during inflation, using the most recent cosmic microwave background (CMB) and large scale structure (LSS) data. Our main focus is on a comparison...
Using BBN in cosmological parameter extraction from CMB: a forecast for Planck (2007)
Hamann, Jan, Lesgourgues, Julien, Mangano, Gianpiero
Data from future high-precision Cosmic Microwave Background (CMB) measurements will be sensitive to the primordial Helium abundance $Y_p$. At the same time, this parameter can be predicted from Big...
Constraining neutrino masses with the ISW-galaxy correlation function (2007)
Lesgourgues, Julien, Valkenburg, Wessel, Gaztanaga, Enrique
Temperature anisotropies in the Cosmic Microwave Background (CMB) are affected by the late Integrated Sachs-Wolfe (lISW) effect caused by any time-variation of the gravitational potential on linear...
What do WMAP and SDSS really tell about inflation? (2007)
Lesgourgues, Julien, Starobinsky, Alexei A., Valkenburg, Wessel
We derive new constraints on the Hubble function H(phi) and subsequently on the inflationary potential V(phi) from WMAP 3-year data combined with the Sloan Luminous Red Galaxy survey (SDSS-LRG),...
New constraints on the observable inflaton potential from WMAP and SDSS (2007)
Lesgourgues, Julien, Valkenburg, Wessel
We derive some new constraints on single-field inflation from the Wilkinson Microwave Anisotropy Probe 3-year data combined with the Sloan Luminous Red Galaxy survey. Our work differs from previous...
Probing cosmological parameters with the CMB: Forecasts from full Monte Carlo simulations (2006)
Perotto, Laurence, Lesgourgues, Julien, Hannestad, Steen, Tu, Huitzu, Wong, Yvonne Y. Y.
The Fisher matrix formalism has in recent times become the standard method for predicting the precision with which various cosmological parameters can be extracted from future data. This approach is...
Isocurvature bounds on axions revisited (2006)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien
The axion is one of the best motivated candidates for particle dark matter. We study and update the constraints imposed by the recent CMB and LSS experiments on the mass of axions produced by the...
Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)
Viel, M, Lesgourgues, Julien, Hähnelt, M G, Matarrese, S, Riotto, Antonio
We present constraints on the mass of Warm Dark Matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the SDSS (Sloan Digital Sky Survey) Lyman-alpha flux power...
Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)
Viel, Matteo, Lesgourgues, Julien, Haehnelt, Martin G., Matarrese, Sabino, Riotto, Antonio
We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey \lya flux power spectrum at 2.2
Massive neutrinos and cosmology (2006)
Lesgourgues, Julien, Pastor, Sergio
The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and...
Probing cosmological parameters with the CMB: Forecasts from Monte Carlo simulations (2006)
Perotto, Laurence, Lesgourgues, Julien, Hannestad, Steen, Tu, Huitzu, Wong, Yvonne Y. Y.
The Fisher matrix formalism has in recent times become the standard method for predicting the precision with which various cosmological parameters can be extracted from future data. This approach is...
Probing neutrino masses with CMB lensing extraction (2005)
Lesgourgues, Julien, Perotto, Laurence, Pastor, Sergio, Piat, Michel
We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field....
Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data (2005)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Riazuelo, Alain
Generic models for the origin of structure predict a spectrum of initial fluctuations with a mixture of adiabatic and isocurvature perturbations. Using the observed anisotropies of the cosmic...
Squeezing the window on isocurvature modes with the Lyman-alpha forest (2005)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Viel, Matteo
Various recent studies proved that cosmological models with a significant contribution from cold dark matter isocurvature perturbations are still compatible with most recent data on cosmic microwave...
Galactic Halos of Fluid Dark Matter (2005)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
Dwarf spiral galaxies - and in particular the prototypical DDO 154 - are known to be completely dominated by an unseen component. The putative neutralinos - so far the favored explanation for the...
Cosmological constraints on quintessential halos (2005)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
A complex scalar field has recently been suggested to bind galaxies and flatten the rotation curves of spirals. Its cosmological behavior is thoroughly investigated here. Such a field is shown to be...
Quintessential Haloes around Galaxies (2005)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
The nature of the dark matter that binds galaxies remains an open question. The favored candidate has been so far the neutralino. This massive species with evanescent interactions is now in...
Introduction to Cosmology (2005)
Sustained development of particle accelerators was always made possible by adopting emerging technologies. Superconductivity and its ancillary cryogenics are today the key technologies to produce...
CMB lensing extraction and primordial non-Gaussianity (2004)
Lesgourgues, Julien, Liguori, Michele, Matarrese, Sabino, Riotto, Antonio
The next generation of CMB experiments should get a better handle on cosmological parameters by mapping the weak lensing deflection field, which is separable from primary anisotropies thanks to the...
An overview of Cosmology (2004)
While purely philosophical in the early times, and still very speculative at the beginning of the twentieth century, Cosmology has gradually entered into the realm of experimental science over the...
An overview of Cosmology (2004)
While purely philosophical in the early times, and still very speculative at the beginning of the twentieth century, Cosmology has gradually entered into the realm of experimental science over the...
Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data (2004)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Riazuelo, Alain
Generic models for the origin of structure predict a spectrum of initial fluctuations with a mixture of adiabatic and isocurvature perturbations. Using the observed anisotropies of the cosmic...
Probing neutrino masses with future galaxy redshift surveys (2004)
Lesgourgues, Julien, Pastor, Sergio, Perotto, Laurence
We perform a new study of future sensitivities of galaxy redshift surveys to the free-streaming effect caused by neutrino masses, adding the information on cosmological parameters from measurements...
Current cosmological bounds on neutrino masses and relativistic relics (2004)
Crotty, Patrick, Lesgourgues, Julien, Pastor, Sergio
We combine the most recent observations of large-scale structure (2dF and SDSS galaxy surveys) and cosmic microwave anisotropies (WMAP and ACBAR) to put constraints on flat cosmological models where...
Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data (2004)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Riazuelo, Alain
Generic models for the origin of structure predict a spectrum of initial fluctuations with a mixture of adiabatic and isocurvature perturbations. Using the observed anisotropies of the cosmic...
Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data (2004)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Riazuelo, Alain
Generic models for the origin of structure predict a spectrum of initial fluctuations with a mixture of adiabatic and isocurvature perturbations. Using the observed anisotropies of the cosmic...
Goldberger-Wise variations: stabilizing brane models with a bulk scalar (2003)
Braneworld scenarios with compact extra-dimensions need the volume of the extra space to be stabilized. Goldberger and Wise have introduced a simple mechanism, based on the presence of a bulk scalar...
Goldberger-Wise variations: stabilizing brane models with a bulk scalar (2003)
Lesgourgues, Julien, Sorbo, Lorenzo
Braneworld scenarios with compact extra-dimensions need the volume of the extra space to be stabilized. Goldberger and Wise have introduced a simple mechanism, based on the presence of a bulk scalar...
Bounds on isocurvature perturbations from CMB and LSS data (2003)
Crotty, P, García-Bellido, J, Lesgourgues, Julien, Riazuelo, A
We obtain very stringent bounds on the possible cold dark matter, baryon and neutrino isocurvature contributions to the primordial fluctuations in the Universe, using recent cosmic microwave...
Does the small CMB quadrupole moment suggest new physics? (2003)
Cline, J M, Crotty, P, Lesgourgues, Julien
Motivated by WMAP's confirmation of an anomalously low value of the quadrupole moment of the CMB temperature fluctuations, we investigate the effects on the CMB of cutting off the primordial power...
Measuring the cosmological background of relativistic particles with WMAP (2003)
Crotty, P, Lesgourgues, Julien, Pastor, S
We show that the first year results of the Wilkinson Microwave Anisotropy Probe (WMAP) constrain very efficiently the energy density in relativistic particles in the universe. We derive new bounds on...
Measuring the cosmological background of relativistic particles with WMAP (2003)
Crotty, Patrick, Lesgourgues, Julien, Pastor, Sergio
We show that the first year results of the Wilkinson Microwave Anisotropy Probe (WMAP) constrain very efficiently the energy density in relativistic particles in the universe. We derive new bounds on...
Galactic Halos of Fluid Dark Matter (2003)
Arbey, A, Lesgourgues, Julien, Salati, Pierre
Dwarf spiral galaxies - and in particular the prototypical DDO 154 - are known to be completely dominated by an unseen component. The putative neutralinos - so far the favored explanation for the...
Galactic Halos of Fluid Dark Matter (2003)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
Dwarf spiral galaxies - and in particular the prototypical DDO 154 - are known to be completely dominated by an unseen component. The putative neutralinos - so far the favored explanation for the...
Galactic Halos of Fluid Dark Matter (2003)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
Dwarf spiral galaxies - and in particular the prototypical DDO 154 - are known to be completely dominated by an unseen component. The putative neutralinos - so far the favored explanation for the...
Galactic Halos of Fluid Dark Matter (2003)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
Dwarf spiral galaxies - and in particular the prototypical DDO 154 - are known to be completely dominated by an unseen component. The putative neutralinos - so far the favored explanation for the...
Transdimensional physics and inflation (2002)
Giudice, Gian Francesco, Kolb, Edward W, Lesgourgues, Julien, Riotto, Antonio
Within the framework of a five-dimensional brane world with a stabilized radion, we compute the cosmological perturbations generated during inflation and show that the perturbations are a powerful...
Cosmological constraints on quintessential halos (2002)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
A complex scalar field has recently been suggested to bind galaxies and flatten the rotation curves of spirals. Its cosmological behavior is thoroughly investigated here. Such a field is shown to be...
Cosmological constraints on quintessential halos (2002)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
A complex scalar field has recently been suggested to bind galaxies and flatten the rotation curves of spirals. Its cosmological behavior is thoroughly investigated here. Such a field is shown to be...
Cosmological constraints on quintessential halos (2001)
Arbey, A, Lesgourgues, Julien, Salati, Pierre
A complex scalar field has recently been suggested to bind galaxies and flatten the rotation curves of spirals. Its cosmological behavior is thoroughly investigated here. Such a field is shown to be...
Cosmological constraints on quintessential halos (2001)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
A complex scalar field has recently been suggested to bind galaxies and flatten the rotation curves of spirals. Its cosmological behavior is thoroughly investigated here. Such a field is shown to be...
Constraining the window on sterile neutrinos as warm dark matter (2001)
Hansen, Steen H., Lesgourgues, Julien, Pastor, Sergio, Silk, Joseph
Sterile neutrinos may be one of the best Warm Dark Matter candidates we have today. Both lower and upper bounds on the mass of the sterile neutrino come from astronomical observations. We show that...
Quintessential Haloes around Galaxies (2001)
Arbey, A, Lesgourgues, Julien, Salati, Pierre
The nature of the dark matter that binds galaxies remains an open question. The favoured candidate has been so far the neutralino. This massive species with evanescent interactions is now in...
Quintessential Haloes around Galaxies (2001)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
The nature of the dark matter that binds galaxies remains an open question. The favored candidate has been so far the neutralino. This massive species with evanescent interactions is now in...
The lepton asymmetry: the last chance for a critical-density cosmology? (2001)
Lesgourgues, Julien, Liddle, A R
We use a wide range of observations to constrain cosmological models possessing a significant asymmetry in the lepton sector, which offer perhaps the best chance of reconciling a critical-density...
The lepton asymmetry: the last chance for a critical-density cosmology? (2001)
Lesgourgues, Julien, Liddle, Andrew R.
We use a wide range of observations to constrain cosmological models possessing a significant asymmetry in the lepton sector, which offer perhaps the best chance of reconciling a critical-density...
Quintessential Haloes around Galaxies (2001)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
The nature of the dark matter that binds galaxies remains an open question. The favored candidate has been so far the neutralino. This massive species with evanescent interactions is now in...
Quintessential Haloes around Galaxies (2001)
Arbey, Alexandre, Lesgourgues, Julien, Salati, Pierre
The nature of the dark matter that binds galaxies remains an open question. The favored candidate has been so far the neutralino. This massive species with evanescent interactions is now in...
Remarks on the Boomerang results, the baryon density and the leptonic asymmetry (2000)
Lesgourgues, Julien, Peloso, Marco
The very recent Boomerang results give an estimate of unprecedented precision of the Cosmic Microwave Background anisotropies on sub--degree scales. A puzzling feature for theoretical cosmology is...
Cosmology of the Randall-Sundrum model after dilaton stabilization (2000)
Lesgourgues, Julien, Pastor, Sergio, Peloso, Marco, Sorbo, Lorenzo
We provide the first complete analysis of cosmological evolution in the Randall-Sundrum model with stabilized dilaton. We give the exact expansion law for matter densities on the two branes with...
Cosmology of the Randall-Sundrum model after dilaton stabilization (2000)
Lesgourgues, Julien, Pastor, Sergio, Peloso, Marco, Sorbo, Lorenzo
Remarks on the Boomerang results, the baryon density and the leptonic asymmetry (2000)
Lesgourgues, Julien, Peloso, Marco
The very recent Boomerang results give an estimate of unprecedented precision of the Cosmic Microwave Background anisotropies on sub–degree scales. A puzzling feature for theoretical cosmology is...
Features in the primordial power spectrum of double D-term inflation (1999)
Recently, there has been some interest for building supersymmetric models of double inflation. These models, realistic from a particle physics point of view, predict a broken-scale-invariant power...
Relic neutrino asymmetry, CMB and large-scale structure (1999)
Pastor, Sergio, Lesgourgues, Julien
We consider some consequences of the presence of a cosmological lepton asymmetry in the form of neutrinos. A relic neutrino degeneracy enhances the contribution of massive neutrinos to the present...
Cosmological implications of a Relic Neutrino Asymmetry (1999)
Lesgourgues, Julien, Pastor, Sergio
We consider some consequences of the presence of a cosmological lepton asymmetry in the form of neutrinos. Relic neutrino degeneracy enhances the contribution of massive neutrinos to the present...
Detectability of the primordial origin of the gravitational wave background in the Universe (1999)
Lesgourgues, Julien, Polarski, David, Prunet, Simon, Starobinski, A. A.
The appearance of peaks in the Fourier power spectra of various primordial fluctuations is a generic prediction of the inflationary scenario. We investigate whether future experiments, in particular...
Large primordial gravitational wave background in a class of BSL ACDM models (1999)
Lesgourgues, Julien, Polarski, David, Starobinsky, A.A.
We consider the primordial gravitational wave (GW) background in a class of spatially-flat inflationary cosmological models with cold dark matter (CDM), a cosmological constant, and a...
Double D-term inflation (1999)
Comparisons of cosmological models to current data show that the presence of a non-trivial feature in the primordial power spectrum of fluctuations, around the scale k = 0.05 h/Mpc, is an open and...
Lesgourgues, Julien, Prunet, Simon, Polarski, David
We consider a class of spatially flat cold dark matter (CDM) models, with a cosmological constant and a broken-scale-invariant (BSI) steplike primordial spectrum of adiabatic perturbations,...
Double D-term inflation (1998)
Comparisons of cosmological models to current data show that the presence of a non-trivial feature in the primordial power spectrum of fluctuations, around the scale k=0.05 h/Mpc, is an open and...
On the Phase-Space Volume of Primordial Cosmological Perturbations (1998)
Lesgourgues, Julien, Polarski, David, Starobinsky, Alexei A.
We show how to determine the typical phase space volume $\Gamma$ for primordial gravitational waves produced during an inflationary stage, which is invariant under squeezing. An expression for...
The Coherence of Primordial Fluctuations Produced During Inflation (1998)
Kiefer, Claus, Lesgourgues, Julien, Polarski, David, Starobinsky, Alexei A.
The behaviour of quantum metric perturbations produced during inflation is considered at the stage after the second Hubble radius crossing. It is shown that the classical correlation between...
CMB anisotropy predictions for a model of double inflation (1997)
Lesgourgues, Julien, Polarski, David
We consider a double-inflationary model with two massive scalar fields interacting only gravitationally in the context of a flat cold dark matter (CDM) Universe. The cosmic microwave background (CMB)...
Quantum-to-classical Transition of Cosmological Perturbations for Non-vacuum Initial States (1996)
Lesgourgues, Julien, Polarski, David, Starobinsky, Alexei A.
Transition from quantum to semiclassical behaviour and loss of quantum coherence for inhomogeneous perturbations generated from a non-vacuum initial state in the early Universe is considered in the...