Observing the Inflationary Reheating
  Reheating is the the epoch which connects inflation to the subsequent hot
Big-Bang phase. Conceptually very important, this era is however
observationally poorly known. We show that the current Planck satellite
measurements of the Cosmic Microwave Background (CMB) anisotropies constrain
the kinematic properties of the reheating era for most of the inflationary
models. This result is obtained by deriving the marginalized posterior
distributions of the reheating parameter for about 200 models taken in
Encyclopaedia Inflationaris. Weighted by the statistical evidence of each model
to explain the data, we show that the Planck 2013 measurements induce an
average reduction of the posterior-to-prior volume by 40%. Making some
additional assumptions on reheating, such as specifying a mean equation of
state parameter, or focusing the analysis on peculiar scenarios, can enhance or
reduce this constraint. Our study also indicates that the Bayesian evidence of
a model can substantially be affected by the reheating properties. The
precision of the current CMB data is therefore such that estimating the
observational performance of a model now requires to incorporate information
about its reheating history.
