CMB constraints on a physical model of reionization

Understand

We study constraints on allowed reionization histories by comparing predictions of a physical semi-numerical model with secondary temperature and polarization anisotropies of the cosmic microwave background (CMB).

• Our model has four free parameters characterizing the evolution of ionizing efficiency $\zeta$ and the minimum mass $M_{\mathrm{min}}$ of haloes that can produce ionizing radiation.
• Comparing the model predictions with the presently available data of the optical depth $\tau$ and kinematic Sunyaev-Zeldovich signal, we find that we can already rule out a significant region of the parameter space.
• We limit the duration of reionization $\Delta z=1.30^{+0.19}_{-0.60}$ ($\Delta z < 2.9$ at $99\%$ C.L.), one of the tightest constraints on the parameter.