Publications de Benjamin Audren

Robustness of cosmic neutrino background detection in the cosmic microwave background

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

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

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

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

Separate constraints on early and late cosmology

Benjamin Audren

Since the public release of Planck data, several attempts have been made to explain the observed small tensions with other data sets, most of them involving an extension of the Lambda cold dark matter (Lambda CDM) model. We try here an alternative approach ...

Oxford Univ Press2014

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

Neutrino and Dark Matter Properties from Cosmological Observations

Benjamin Audren

We apply the principles of Bayesian statistics to the main probes of cosmology, in order to refine our knowledge of the Standard Model and possibly extend it. Notably, we investigate the basic elements of the model in detail in order to reinforce this basi ...

EPFL2014

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

Conservative constraints on early cosmology with MONTE PYTHON

Julien Lesgourgues, Benjamin Audren

Models for the latest stages of the cosmological evolution rely on a less solid theoretical and observational ground than the description of earlier stages like BBN and recombination. As suggested in a previous work by Vonlanthen et al., it is possible to ...

Iop Publishing Ltd2013

Cosmological constraints on Lorentz violating dark energy

Sergey Sibiryakov, Julien Lesgourgues, 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

CMB photons shedding light on dark matter

Gaëlle Giesen, Julien Lesgourgues, Benjamin Audren

The annihilation or decay of Dark Matter (DM) particles could affect the thermal history of the universe and leave an observable signature in Cosmic Microwave Background (CMB) anisotropies. We update constraints on the annihilation rate of DM particles in ...

Iop Publishing Ltd2012

Non-linear matter power spectrum from Time Renormalisation Group: efficient computation and comparison with one-loop

Julien Lesgourgues, Benjamin Audren

We address the issue of computing the non-linear matter power spectrum on mildly non-linear scales with efficient semi-analytic methods. We implemented M. Pietroni's Time Renormalization Group (TRG) method and its Dynamical 1-Loop (D1L) limit in a numerica ...

2011