Zero-metallicity stellar sources and the reionization epoch

Citation
P. Cojazzi et al., Zero-metallicity stellar sources and the reionization epoch, M NOT R AST, 315(4), 2000, pp. L51-L55
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
ISSN journal
0035-8711 → ACNP
Volume
315
Issue
4
Year of publication
2000
Pages
L51 - L55
Database
ISI
SICI code
0035-8711(20000711)315:4<L51:ZSSATR>2.0.ZU;2-Y
Abstract
We reconsider the problem of the cosmological reionization owing to stellar sources. Using a method similar to that developed by Haiman & Loeb, we inv estigate 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 na tural choice for the first stellar populations. We construct young isochron es representative of Population III stars from existing sets of evolutionar y models (by Forieri and Cassisi & Castellani) and calculate a suitable lib rary of zero-metallicity model atmospheres. The number of ionizing photons emitted by such a zero-metal population is about 40 per cent higher than th at produced by standard metal-poor isochrones. We find that adopting suitab le zero-metallicity models modifies the reionization epoch. However the lat ter is still largely affected by current uncertainties in other important p hysical processes such as the efficiency of the star formation and the frac tion of escaping UV photons.