Open AccessUpdating reionization scenarios after recent data
Author(s) -
Choudhury T. Roy,
Ferrara A.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2006.00207.x
Subject(s) - reionization , physics , astrophysics , cmb cold spot , stars , radiative transfer , redshift , astronomy , cosmic microwave background , galaxy , optics , anisotropy
ABSTRACT The recent release of data on (i) high‐redshift source counts from the Near Infrared Camera and Multi‐Object Spectrometer (NICMOS) Hubble Ultra Deep Field (HUDF) and (ii) electron scattering optical depth from the Wilkinson Microwave Anisotropy Probe ( WMAP ) requires a re‐examination of reionization scenarios. Using an improved self‐consistent reionization model, based on Choudhury & Ferrara, we determine the range of reionization histories which can match a wide variety of data sets simultaneously. The updated constraints from our analysis imply that hydrogen reionization starts at around z ≈ 15 , driven by the metal‐free Population III (PopIII) stars (with normal Salpeter‐like initial mass functions), and it is 90 per cent complete by z ≈ 10 . The photoionizing power of the PopIII stars fades for z ≲ 10 because of concomitant action radiative and chemical feedbacks, which causes the reionization process to stretch considerably and to end only by z ≈ 6 . The combination of different data sets still favours a non‐zero contribution from metal‐free stars, with star‐forming efficiencies larger than 2 per cent.