Powering reionization: assessing the galaxy ionizing photon budget at $z
< 10$
K. Duncan, and C. Conselice. (2015)cite arxiv:1505.01846Comment: Accepted for publication in MNRAS.
Abstract
We present a new analysis of the ionizing emissivity ($N_ion$,
s$^-1$ Mpc$^-3$) for galaxies during the epoch of reionization and their
potential for completing and maintaining reionization. We use extensive SED
modelling -- incorporating two plausible mechanisms for the escape of Lyman
continuum photon -- to explore the range and evolution of ionizing efficiencies
consistent with new results on galaxy colours ($\beta$) during this epoch. We
estimate $N_ion$ for the latest observations of the luminosity and
star-formation rate density at $z<10$, outlining the range of emissivity
histories consistent with our new model. Given the growing observational
evidence for a UV colour-magnitude relation in high-redshift galaxies, we find
that for any plausible evolution in galaxy properties, red (brighter) galaxies
are less efficient at producing ionizing photons than their blue (fainter)
counterparts. The assumption of a redshift and luminosity evolution in $\beta$
leads to two important conclusions. Firstly, the ionizing efficiency of
galaxies naturally increases with redshift. Secondly, for a luminosity
dependent ionizing efficiency, we find that galaxies down to a rest-frame
magnitude of $M_UV -15$ alone can potentially produce sufficient
numbers of ionizing photons to maintain reionization as early as $z\sim8$ for a
clumping factor of $C_H II 3$.
Description
[1505.01846] Powering reionization: assessing the galaxy ionizing photon budget at $z < 10$
%0 Generic
%1 duncan2015powering
%A Duncan, Kenneth
%A Conselice, Christopher J
%D 2015
%K budget galaxy photon reionization
%T Powering reionization: assessing the galaxy ionizing photon budget at $z
< 10$
%U http://arxiv.org/abs/1505.01846
%X We present a new analysis of the ionizing emissivity ($N_ion$,
s$^-1$ Mpc$^-3$) for galaxies during the epoch of reionization and their
potential for completing and maintaining reionization. We use extensive SED
modelling -- incorporating two plausible mechanisms for the escape of Lyman
continuum photon -- to explore the range and evolution of ionizing efficiencies
consistent with new results on galaxy colours ($\beta$) during this epoch. We
estimate $N_ion$ for the latest observations of the luminosity and
star-formation rate density at $z<10$, outlining the range of emissivity
histories consistent with our new model. Given the growing observational
evidence for a UV colour-magnitude relation in high-redshift galaxies, we find
that for any plausible evolution in galaxy properties, red (brighter) galaxies
are less efficient at producing ionizing photons than their blue (fainter)
counterparts. The assumption of a redshift and luminosity evolution in $\beta$
leads to two important conclusions. Firstly, the ionizing efficiency of
galaxies naturally increases with redshift. Secondly, for a luminosity
dependent ionizing efficiency, we find that galaxies down to a rest-frame
magnitude of $M_UV -15$ alone can potentially produce sufficient
numbers of ionizing photons to maintain reionization as early as $z\sim8$ for a
clumping factor of $C_H II 3$.
@misc{duncan2015powering,
abstract = {We present a new analysis of the ionizing emissivity ($\dot{N}_{\rm{ion}}$,
s$^{-1}$ Mpc$^{-3}$) for galaxies during the epoch of reionization and their
potential for completing and maintaining reionization. We use extensive SED
modelling -- incorporating two plausible mechanisms for the escape of Lyman
continuum photon -- to explore the range and evolution of ionizing efficiencies
consistent with new results on galaxy colours ($\beta$) during this epoch. We
estimate $\dot{N}_{\rm{ion}}$ for the latest observations of the luminosity and
star-formation rate density at $z<10$, outlining the range of emissivity
histories consistent with our new model. Given the growing observational
evidence for a UV colour-magnitude relation in high-redshift galaxies, we find
that for any plausible evolution in galaxy properties, red (brighter) galaxies
are less efficient at producing ionizing photons than their blue (fainter)
counterparts. The assumption of a redshift and luminosity evolution in $\beta$
leads to two important conclusions. Firstly, the ionizing efficiency of
galaxies naturally increases with redshift. Secondly, for a luminosity
dependent ionizing efficiency, we find that galaxies down to a rest-frame
magnitude of $M_{\rm{UV}} \approx -15$ alone can potentially produce sufficient
numbers of ionizing photons to maintain reionization as early as $z\sim8$ for a
clumping factor of $C_{\rm{H {\small II}}} \leq 3$.},
added-at = {2015-05-11T10:29:20.000+0200},
author = {Duncan, Kenneth and Conselice, Christopher J},
biburl = {https://www.bibsonomy.org/bibtex/2bcf68b39ca75350a71711f9d5c872ef4/miki},
description = {[1505.01846] Powering reionization: assessing the galaxy ionizing photon budget at $z < 10$},
interhash = {c7f749fde57a29f99ba565c5da284371},
intrahash = {bcf68b39ca75350a71711f9d5c872ef4},
keywords = {budget galaxy photon reionization},
note = {cite arxiv:1505.01846Comment: Accepted for publication in MNRAS},
timestamp = {2015-05-11T10:29:20.000+0200},
title = {Powering reionization: assessing the galaxy ionizing photon budget at $z
< 10$},
url = {http://arxiv.org/abs/1505.01846},
year = 2015
}