Year: 2015
Type: article
Abstract: Cosmic reionization holds the key to understand structure formation in the Universe, and can inform us about the properties of the first sources, as their star formation efficiency and escape fraction of ionizing photons. By combining the recent release of Planck electron scattering optical depth data with observations of high-redshift quasar absorption spectra, we obtain strong constraints on viable reionization histories. We show that inclusion of Planck data favors a reionization scenario with a single stellar population. The mean xH i drops from ∼0.8 at z = 10.6 to ∼10−4 at z = 5.8 and reionization is completed around 5.8 ≲ z ≲ 8.5 (2σ), thus indicating a significant reduction in contributions to reionization from high-redshift sources. We can put independent constraints on the escape fraction fesc of ionizing photons by incorporating the high-redshift galaxy luminosity function data into our analysis. We find a non-evolving fesc of ∼10 per cent in the redshift range z = 6−9.
Authors: Sourav Mitra, T. Roy Choudhury, Andrea Ferrara
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1956810680