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ID 14647
file
creator
Murakami, T.
Yonetoku, M.
Umemura, M.
Matsubayashi, T.
Yamazaki, Ryo
subject
early universe
gamma ryas
bursts
stars
formation
NDC
Astronomy. Space sciences
abstract
Based on the gamma-ray burst event rate at redshifts of 4 ≤ z ≤ 12 which is assessed by the spectral peak energy-to-luminosity relation recently found by Yonetoku et al., we observationally derive the star formation (SFR) for Population III (Pop. III) stars in a high-redshift universe. As a result, we find that Pop. III stars form continuously at. Using the derived Pop. III SFR, we attempt to estimate the ultraviolet (UV) photon emission rate at in which redshift range no observational information has been hitherto 7 ≤ z ≤ 12 on ionizing radiation intensity. We find that the UV emissivity at can make a noticeable 7 ≤ z ≤ 12 to the early reionization. The maximal emissivity is higher than the level required to keep ionizing the matter (IGM) at. However, if the escape fraction of ionizing photons from Pop. III objects is 7 ≤ z ≤ 12 than 10%, then the IGM can be neutralized at some redshift, which may lead to the double reionization. As the enrichment, the ejection of all metals synthesized in Pop. III objects is marginally consistent with the metallicity, although the confinement of metals in Pop. III objects can reduce the enrichment significantly.
journal title
Astrophysical Journal
volume
Volume 625
issue
Issue 1
start page
L13
end page
L16
date of issued
2005-05
publisher
University of Chicago Press
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) 2005 The American Astronomical Society
relation is version of URL
http://dx.doi.org/10.1086/430828
department
Graduate School of Science



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