Understand
Using a Bayesian framework, we quantify what current observations imply about the history of the epoch of reionisation (EoR).
- We use a popular, three-parameter EoR model, flexible enough to accommodate a wide range of physically-plausible reionisation histories.
- We study the impact of various EoR observations: (i) the optical depth to the CMB measured by Planck 2016; (ii) the dark fraction in the Lyman $\alpha$ and $\beta$ forests; (iii) the redshift evolution of galactic Ly$\alpha$ emission (so-called "Ly$\alpha$ fraction"); (iv) the clustering of Ly$\alpha$ emitters; (v) the IGM damping wing imprint in the spectrum of QSO ULASJ1120+0641; (vi) and the patchy kinetic Sunyaev-Zel'dovich signal.
- Combined, (i) and (ii) already place interesting constraints on the reionisation history, with the epochs corresponding to an average neutral fraction of (75, 50, 25) per cent, constrained at 1$\sigma$ to $z= (9.21\substack{+1.22 -1.15}, 8.14\substack{+1.08 -1.00}, 7.26\substack{+1.13 -0.96})$.