Journal Article

Reionization and feedback in overdense regions at high redshift

Girish Kulkarni and T. Roy Choudhury

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 412, issue 4, pages 2781-2789
Published in print April 2011 | ISSN: 0035-8711
Published online April 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.18100.x
Reionization and feedback in overdense regions at high redshift

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Observations of galaxy luminosity function at high redshifts typically focus on fields of view of limited sizes preferentially containing bright sources. These regions possibly are overdense and hence biased with respect to the globally averaged regions. Using a semi-analytic model based on Choudhury & Ferrara (2006) which is calibrated to match a wide range of observations, we study the reionization and thermal history of the Universe in overdense regions. The main results of our calculation are as follows. (i) Reionization and thermal histories in the biased regions are markedly different from the average ones because of enhanced number of sources and higher radiative feedback. (ii) The galaxy luminosity function for biased regions is markedly different from those corresponding to average ones. In particular, the effect of radiative feedback arising from cosmic reionization is visible at much brighter luminosities. (iii) Because of the enhanced radiative feedback within overdense locations, the luminosity function in such regions is more sensitive to reionization history than in average regions. The effect of feedback is visible for absolute AB magnitude MAB≳−17 at z= 8, almost within the reach of present-day observations and surely to be probed by the James Webb Space Telescope. This could possibly serve as an additional probe of radiative feedback and hence reionization at high redshifts.

Keywords: galaxies: high-redshift; galaxies: luminosity function, mass function; cosmology: theory; dark ages, reionization, first stars

Journal Article.  7043 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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