Benjamin Audren

CMB photons shedding light on dark matter

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 the smooth cosmological background, using WMAP7 and recent small-scale CMB data. With a systematic analysis based on the Press-Schechter formalism, we also show that DM annihilation in halos at small redshift may explain entirely the reionization patterns observed in the CMB, under reasonable assumptions concerning the concentration and formation redshift of halos. We find that a mixed reionization model based on DM annihilation in halos as well as star formation at a redshift z similar or equal to 6.5 could simultaneously account for CMB observations and satisfy constraints inferred from the Gunn-Peterson effect. However, these models tend to reheat the inter-galactic medium (IGM) well above observational bounds: by including a realistic prior on the IGM temperature at low redshift and allowing most of the reionization to be due to star formation, we find stronger cosmological bounds on the annihilation cross-section than with the CMB alone.

Strongest model-independent bound on the lifetime of Dark Matter

Dark Matter is essential for structure formation in the late Universe so it must be stable on cosmological time scales. But how stable exactly? Only assuming decays into relativistic particles, we report an otherwise model independent bound on the lifetime of Dark Matter using current cosmological data. Since these decays affect only the low-

Cosmological constraints on Lorentz violating dark energy

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

multipoles of the CMB, the Dark Matter lifetime is expected to correlate with the tensor-to-scalar ratio

Robustness of cosmic neutrino background detection in the cosmic microwave background

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

as well as curvature

Separate constraints on early and late cosmology

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Semi-analytical computation of the non-linear matter power spectrum

. We consider two models, including

Conservative constraints on early cosmology with MONTE PYTHON

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A note of clarification: BICEP2 and Planck are not in tension

and