Open AccessZero‐metallicity stellar sources and the reionization epoch
Author(s) -
Cojazzi Paolo,
Bressan Alessandro,
Lucchin Francesco,
Pantano Ornella,
Chavez Miguel
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03670.x
Subject(s) - reionization , physics , metallicity , astrophysics , stars , stellar population , astronomy , population , star formation , photon , galaxy , quantum mechanics , demography , redshift , sociology
We reconsider the problem of the cosmological reionization owing to stellar sources. Using a method similar to that developed by Haiman & Loeb, we investigate the effect of changing the stellar models and the stellar spectra adopted for deriving the ionizing photon production rate. In particular, we study the consequences of adopting zero‐metallicity stars, which is the natural choice for the first stellar populations. We construct young isochrones representative of Population III stars from existing sets of evolutionary models (by Forieri and Cassisi & Castellani) and calculate a suitable library of zero‐metallicity model atmospheres. The number of ionizing photons emitted by such a zero‐metal population is about 40 per cent higher than that produced by standard metal‐poor isochrones. We find that adopting suitable zero‐metallicity models modifies the reionization epoch. However the latter is still largely affected by current uncertainties in other important physical processes such as the efficiency of the star formation and the fraction of escaping UV photons.