A new model framework for circumgalactic Ly$\alpha$ radiative transfer
constrained by galaxy-Ly$\alpha$ forest clustering
K. Kakiichi, and M. Dijkstra. (2017)cite arxiv:1710.10053Comment: 20 pages, 14 figures, submitted to MNRAS.
Abstract
We present a new perturbative approach to "constrained Ly$\alpha$ radiative
transfer'" (RT) through the circum- and inter-galactic medium (CGM and IGM). We
constrain the HI content and kinematics of the CGM and IGM in a physically
motivated model, using the galaxy-Ly$\alpha$ forest clustering data from
spectroscopic galaxy surveys in QSO fields at $z\sim2-3$. This enables us to
quantify the impact of the CGM/IGM on Ly$\alpha$ emission in an observationally
constrained, realistic cosmological environment. Our model predicts that the
CGM and IGM at these redshifts transmit $\approx80~\%$ of Ly$\alpha$ photons
after having escaped from galaxies. This implies that while the inter-stellar
medium primarily regulates Ly$\alpha$ escape, the CGM has a non-negligible
impact on the observed Ly$\alpha$ line properties and the inferred Ly$\alpha$
escape fraction, even at $z2-3$. Ly$\alpha$ scattering in the CGM and IGM
further introduces an environmental dependence in the (apparent) Ly$\alpha$
escape fraction, and the observed population of Ly$\alpha$ emitting galaxies:
the CGM/IGM more strongly suppresses direct Ly$\alpha$ emission from galaxies
in overdense regions in the Universe, and redistributes this emission into
brighter Ly$\alpha$ haloes. The resulting mean surface brightness profile of
the Ly$\alpha$ haloes is generally found to be a power-law $r^-2.4$.
Our results demonstrate how (integral field) spectroscopic surveys of galaxies
in QSO fields constrain circumgalactic Ly$\alpha$ RT, and we discuss the
potential of these models for studying CGM physics, reionization and cosmology.
Description
[1710.10053] A new model framework for circumgalactic Ly$\alpha$ radiative transfer constrained by galaxy-Ly$\alpha$ forest clustering
%0 Generic
%1 kakiichi2017model
%A Kakiichi, Koki
%A Dijkstra, Mark
%D 2017
%K CGM Lya radiative transfer
%T A new model framework for circumgalactic Ly$\alpha$ radiative transfer
constrained by galaxy-Ly$\alpha$ forest clustering
%U http://arxiv.org/abs/1710.10053
%X We present a new perturbative approach to "constrained Ly$\alpha$ radiative
transfer'" (RT) through the circum- and inter-galactic medium (CGM and IGM). We
constrain the HI content and kinematics of the CGM and IGM in a physically
motivated model, using the galaxy-Ly$\alpha$ forest clustering data from
spectroscopic galaxy surveys in QSO fields at $z\sim2-3$. This enables us to
quantify the impact of the CGM/IGM on Ly$\alpha$ emission in an observationally
constrained, realistic cosmological environment. Our model predicts that the
CGM and IGM at these redshifts transmit $\approx80~\%$ of Ly$\alpha$ photons
after having escaped from galaxies. This implies that while the inter-stellar
medium primarily regulates Ly$\alpha$ escape, the CGM has a non-negligible
impact on the observed Ly$\alpha$ line properties and the inferred Ly$\alpha$
escape fraction, even at $z2-3$. Ly$\alpha$ scattering in the CGM and IGM
further introduces an environmental dependence in the (apparent) Ly$\alpha$
escape fraction, and the observed population of Ly$\alpha$ emitting galaxies:
the CGM/IGM more strongly suppresses direct Ly$\alpha$ emission from galaxies
in overdense regions in the Universe, and redistributes this emission into
brighter Ly$\alpha$ haloes. The resulting mean surface brightness profile of
the Ly$\alpha$ haloes is generally found to be a power-law $r^-2.4$.
Our results demonstrate how (integral field) spectroscopic surveys of galaxies
in QSO fields constrain circumgalactic Ly$\alpha$ RT, and we discuss the
potential of these models for studying CGM physics, reionization and cosmology.
@misc{kakiichi2017model,
abstract = {We present a new perturbative approach to "constrained Ly$\alpha$ radiative
transfer'" (RT) through the circum- and inter-galactic medium (CGM and IGM). We
constrain the HI content and kinematics of the CGM and IGM in a physically
motivated model, using the galaxy-Ly$\alpha$ forest clustering data from
spectroscopic galaxy surveys in QSO fields at $z\sim2-3$. This enables us to
quantify the impact of the CGM/IGM on Ly$\alpha$ emission in an observationally
constrained, realistic cosmological environment. Our model predicts that the
CGM and IGM at these redshifts transmit $\approx80~\%$ of Ly$\alpha$ photons
after having escaped from galaxies. This implies that while the inter-stellar
medium primarily regulates Ly$\alpha$ escape, the CGM has a non-negligible
impact on the observed Ly$\alpha$ line properties and the inferred Ly$\alpha$
escape fraction, even at $z\sim 2-3$. Ly$\alpha$ scattering in the CGM and IGM
further introduces an environmental dependence in the (apparent) Ly$\alpha$
escape fraction, and the observed population of Ly$\alpha$ emitting galaxies:
the CGM/IGM more strongly suppresses direct Ly$\alpha$ emission from galaxies
in overdense regions in the Universe, and redistributes this emission into
brighter Ly$\alpha$ haloes. The resulting mean surface brightness profile of
the Ly$\alpha$ haloes is generally found to be a power-law $\propto r^{-2.4}$.
Our results demonstrate how (integral field) spectroscopic surveys of galaxies
in QSO fields constrain circumgalactic Ly$\alpha$ RT, and we discuss the
potential of these models for studying CGM physics, reionization and cosmology.},
added-at = {2017-10-30T10:07:44.000+0100},
author = {Kakiichi, Koki and Dijkstra, Mark},
biburl = {https://www.bibsonomy.org/bibtex/27ee5e469f14bffdb6177a07708ac7c37/miki},
description = {[1710.10053] A new model framework for circumgalactic Ly$\alpha$ radiative transfer constrained by galaxy-Ly$\alpha$ forest clustering},
interhash = {6ef5a34e21a78626b1b94e7a570cb91d},
intrahash = {7ee5e469f14bffdb6177a07708ac7c37},
keywords = {CGM Lya radiative transfer},
note = {cite arxiv:1710.10053Comment: 20 pages, 14 figures, submitted to MNRAS},
timestamp = {2017-10-30T10:07:44.000+0100},
title = {A new model framework for circumgalactic Ly$\alpha$ radiative transfer
constrained by galaxy-Ly$\alpha$ forest clustering},
url = {http://arxiv.org/abs/1710.10053},
year = 2017
}