The kinetic Sunyaev–Zel’dovich effect from reionization

During the epoch of reionization, local variations in the ionized fraction (patchiness) imprint arcminute-scale temperature anisotropies in the cosmic microwave background through the kinetic Sunyaev–Zel’dovich (kSZ) effect. We employ an analytic model of reionization devised by Furlanetto and coworkers to calculate the kSZ anisotropies for patchy reionization. We find that the angular power spectrum of the kSZ anisotropies depends strongly on the size distribution of the HII bubbles and on the duration of reionization. In addition, we show that upcoming measurements of the kSZ effect should be able to distinguish between several popular reionization scenarios. In particular, the amplitude of the patchy power spectrum for reionization scenarios in which the IGM is significantly ionized by Population III stars (or by mini-quasars/decaying particles) can be larger (or smaller) by over a factor of 3 than the amplitude in more traditional reionization histories (with temperature anisotropies that range between 0.5 and 3 μK at l = 5000).