%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 $z &lt; 10$}, 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 }