Cosmic reionization in dynamic quintessence cosmology

In this paper, we investigate the effects that a dynamic dark energy component dominant in the universe at late epochs has on reionization. We follow the evolution of H ii regions with the analytic approach of Furlanetto & Oh in two different universes for which we assume the Peebles & Ratra and Brax & Martin quintessence models and we compare our results to the Λ cold dark matter (ΛCDM) scenario. We show that, for a fixed ionization efficiency, at the same cosmological epoch the morphology of bubbles is dominated by high-mass objects and the characteristic size of the ionized regions is slightly smaller than in the ΛCDM model, especially at the latest stages of reionization, due to the higher recombination efficiency. As a consequence, the bubbles' 'epoch of overlap' happens earlier than in ΛCDM. Finally, we show how the different evolution of the H ii regions affects the transmission of the high-z quasi-stellar object spectra, reducing the Lyman flux absorption at small optical depths. © 2008 RAS.