We present a new flexible Bayesian framework for directly inferring the
fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch
of Reionization (EoR, z~6-10) from detections and non-detections of Lyman Alpha
(Ly$\alpha$) emission from Lyman break galaxies (LBGs). Our framework combines
sophisticated reionization simulations with empirical models of the
interstellar medium (ISM) radiative transfer effects on Ly$\alpha$. We assert
that the Ly$\alpha$ line profile emerging from the ISM has an important impact
on the resulting transmission of photons through the IGM, and that these line
profiles depend on galaxy properties. We model this effect by considering the
peak velocity offset of Ly$\alpha$ lines from host galaxies' systemic redshifts
which are empirically correlated with UV luminosity and redshift (or halo mass
at fixed redshift). We use our framework on the sample of LBGs presented in
Pentericci et al. (2014) and infer a global neutral fraction at z~7 of
$x_HI = 0.59_-0.15^+0.11$, consistent with other robust
probes of the EoR and confirming reionization is on-going ~700 Myr after the
Big Bang. We show that using the full distribution of Ly$\alpha$ equivalent
width detections and upper limits from LBGs places tighter constraints on the
evolving IGM than the standard Ly$\alpha$ emitter fraction, and that larger
samples are within reach of deep spectroscopic surveys of gravitationally
lensed fields and JWST NIRSpec.
Description
[1709.05356] The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies
%0 Generic
%1 mason2017universe
%A Mason, Charlotte A.
%A Treu, Tommaso
%A Dijkstra, Mark
%A Mesinger, Andrei
%A Trenti, Michele
%A Pentericci, Laura
%A de Barros, Stephane
%A Vanzella, Eros
%D 2017
%K IGM fraction neutral reionisation
%T The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral
Fraction Using Ly$\alpha$ Emission from Galaxies
%U http://arxiv.org/abs/1709.05356
%X We present a new flexible Bayesian framework for directly inferring the
fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch
of Reionization (EoR, z~6-10) from detections and non-detections of Lyman Alpha
(Ly$\alpha$) emission from Lyman break galaxies (LBGs). Our framework combines
sophisticated reionization simulations with empirical models of the
interstellar medium (ISM) radiative transfer effects on Ly$\alpha$. We assert
that the Ly$\alpha$ line profile emerging from the ISM has an important impact
on the resulting transmission of photons through the IGM, and that these line
profiles depend on galaxy properties. We model this effect by considering the
peak velocity offset of Ly$\alpha$ lines from host galaxies' systemic redshifts
which are empirically correlated with UV luminosity and redshift (or halo mass
at fixed redshift). We use our framework on the sample of LBGs presented in
Pentericci et al. (2014) and infer a global neutral fraction at z~7 of
$x_HI = 0.59_-0.15^+0.11$, consistent with other robust
probes of the EoR and confirming reionization is on-going ~700 Myr after the
Big Bang. We show that using the full distribution of Ly$\alpha$ equivalent
width detections and upper limits from LBGs places tighter constraints on the
evolving IGM than the standard Ly$\alpha$ emitter fraction, and that larger
samples are within reach of deep spectroscopic surveys of gravitationally
lensed fields and JWST NIRSpec.
@misc{mason2017universe,
abstract = {We present a new flexible Bayesian framework for directly inferring the
fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch
of Reionization (EoR, z~6-10) from detections and non-detections of Lyman Alpha
(Ly$\alpha$) emission from Lyman break galaxies (LBGs). Our framework combines
sophisticated reionization simulations with empirical models of the
interstellar medium (ISM) radiative transfer effects on Ly$\alpha$. We assert
that the Ly$\alpha$ line profile emerging from the ISM has an important impact
on the resulting transmission of photons through the IGM, and that these line
profiles depend on galaxy properties. We model this effect by considering the
peak velocity offset of Ly$\alpha$ lines from host galaxies' systemic redshifts
which are empirically correlated with UV luminosity and redshift (or halo mass
at fixed redshift). We use our framework on the sample of LBGs presented in
Pentericci et al. (2014) and infer a global neutral fraction at z~7 of
$\overline{x}_\mathrm{HI} = 0.59_{-0.15}^{+0.11}$, consistent with other robust
probes of the EoR and confirming reionization is on-going ~700 Myr after the
Big Bang. We show that using the full distribution of Ly$\alpha$ equivalent
width detections and upper limits from LBGs places tighter constraints on the
evolving IGM than the standard Ly$\alpha$ emitter fraction, and that larger
samples are within reach of deep spectroscopic surveys of gravitationally
lensed fields and JWST NIRSpec.},
added-at = {2017-09-19T10:30:51.000+0200},
author = {Mason, Charlotte A. and Treu, Tommaso and Dijkstra, Mark and Mesinger, Andrei and Trenti, Michele and Pentericci, Laura and de Barros, Stephane and Vanzella, Eros},
biburl = {https://www.bibsonomy.org/bibtex/2a0f7eaddda72490f4e86c0f7b1abcce9/miki},
description = {[1709.05356] The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies},
interhash = {fb86a5590ce08bde0044cdcc81535e3e},
intrahash = {a0f7eaddda72490f4e86c0f7b1abcce9},
keywords = {IGM fraction neutral reionisation},
note = {cite arxiv:1709.05356Comment: 15 pages, 12 figures. Submitted to ApJ},
timestamp = {2017-09-19T10:30:51.000+0200},
title = {The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral
Fraction Using Ly$\alpha$ Emission from Galaxies},
url = {http://arxiv.org/abs/1709.05356},
year = 2017
}