Ionization bias and the ghost proximity effect near $z\gtrsim6$ quasars
in the shadow of proximate absorption systems
F. Davies. (2019)cite arxiv:1904.10459Comment: 12 pages, 17 figures, submitted to MNRAS.
Аннотация
The larger-than-expected scatter in the opacity of the Ly$\alpha$ forest
suggests that the metagalactic ionizing background is strongly fluctuating at
$z > 5.5$. Models for ionizing background fluctuations predict a strong
positive bias on large scales, so the environments of massive $>10^12\,\rm
M_ødot$ dark matter halos, e.g. $z\sim6$ quasar hosts, would be ideal
laboratories to constrain the sources of ionizing photons. While the quasars
themselves should overwhelm any plausible ionizing photon contribution from
neighboring galaxies, proximate damped Ly$\alpha$ absorbers (DLAs) have
recently been discovered in the foreground of $z\sim6$ quasars, and the
Ly$\alpha$ forest in the shadow of these DLAs could probe the local ionization
environment. Using Gpc$^3$ simulations of $z=6$ ionizing background
fluctuations, we show that while the Ly$\alpha$ forest signal from ionization
bias around a quasar host halo should be strong, it is likely suppressed by the
associated intergalactic matter overdensity. We also show that the quasar
itself may still overwhelm the clustering signal via a "ghost" of the proximity
effect from the quasar radiation causing a large-scale bias in the ionizing
photon mean free path. This ghost proximity effect is sensitive to the lifetime
and geometry of quasar emission, potentially unlocking a new avenue for
constraining these fundamental quasar properties. Finally, we present
observations of a $z\sim6$ quasar with a proximate DLA which shows a strong
excess in Ly$\alpha$ forest transmission at the predicted location of the ghost
proximity effect.
Описание
Ionization bias and the ghost proximity effect near $z\gtrsim6$ quasars in the shadow of proximate absorption systems
%0 Generic
%1 davies2019ionization
%A Davies, Frederick B.
%D 2019
%K library
%T Ionization bias and the ghost proximity effect near $z\gtrsim6$ quasars
in the shadow of proximate absorption systems
%U http://arxiv.org/abs/1904.10459
%X The larger-than-expected scatter in the opacity of the Ly$\alpha$ forest
suggests that the metagalactic ionizing background is strongly fluctuating at
$z > 5.5$. Models for ionizing background fluctuations predict a strong
positive bias on large scales, so the environments of massive $>10^12\,\rm
M_ødot$ dark matter halos, e.g. $z\sim6$ quasar hosts, would be ideal
laboratories to constrain the sources of ionizing photons. While the quasars
themselves should overwhelm any plausible ionizing photon contribution from
neighboring galaxies, proximate damped Ly$\alpha$ absorbers (DLAs) have
recently been discovered in the foreground of $z\sim6$ quasars, and the
Ly$\alpha$ forest in the shadow of these DLAs could probe the local ionization
environment. Using Gpc$^3$ simulations of $z=6$ ionizing background
fluctuations, we show that while the Ly$\alpha$ forest signal from ionization
bias around a quasar host halo should be strong, it is likely suppressed by the
associated intergalactic matter overdensity. We also show that the quasar
itself may still overwhelm the clustering signal via a "ghost" of the proximity
effect from the quasar radiation causing a large-scale bias in the ionizing
photon mean free path. This ghost proximity effect is sensitive to the lifetime
and geometry of quasar emission, potentially unlocking a new avenue for
constraining these fundamental quasar properties. Finally, we present
observations of a $z\sim6$ quasar with a proximate DLA which shows a strong
excess in Ly$\alpha$ forest transmission at the predicted location of the ghost
proximity effect.
@misc{davies2019ionization,
abstract = {The larger-than-expected scatter in the opacity of the Ly$\alpha$ forest
suggests that the metagalactic ionizing background is strongly fluctuating at
$z > 5.5$. Models for ionizing background fluctuations predict a strong
positive bias on large scales, so the environments of massive $>10^{12}\,{\rm
M}_\odot$ dark matter halos, e.g. $z\sim6$ quasar hosts, would be ideal
laboratories to constrain the sources of ionizing photons. While the quasars
themselves should overwhelm any plausible ionizing photon contribution from
neighboring galaxies, proximate damped Ly$\alpha$ absorbers (DLAs) have
recently been discovered in the foreground of $z\sim6$ quasars, and the
Ly$\alpha$ forest in the shadow of these DLAs could probe the local ionization
environment. Using Gpc$^3$ simulations of $z=6$ ionizing background
fluctuations, we show that while the Ly$\alpha$ forest signal from ionization
bias around a quasar host halo should be strong, it is likely suppressed by the
associated intergalactic matter overdensity. We also show that the quasar
itself may still overwhelm the clustering signal via a "ghost" of the proximity
effect from the quasar radiation causing a large-scale bias in the ionizing
photon mean free path. This ghost proximity effect is sensitive to the lifetime
and geometry of quasar emission, potentially unlocking a new avenue for
constraining these fundamental quasar properties. Finally, we present
observations of a $z\sim6$ quasar with a proximate DLA which shows a strong
excess in Ly$\alpha$ forest transmission at the predicted location of the ghost
proximity effect.},
added-at = {2019-04-25T05:07:53.000+0200},
author = {Davies, Frederick B.},
biburl = {https://www.bibsonomy.org/bibtex/27e8e83ad0855e6b36b193f3d658885bb/gpkulkarni},
description = {Ionization bias and the ghost proximity effect near $z\gtrsim6$ quasars in the shadow of proximate absorption systems},
interhash = {0ab604b251fa7da43da9cc21b91b25e4},
intrahash = {7e8e83ad0855e6b36b193f3d658885bb},
keywords = {library},
note = {cite arxiv:1904.10459Comment: 12 pages, 17 figures, submitted to MNRAS},
timestamp = {2019-04-25T05:07:53.000+0200},
title = {Ionization bias and the ghost proximity effect near $z\gtrsim6$ quasars
in the shadow of proximate absorption systems},
url = {http://arxiv.org/abs/1904.10459},
year = 2019
}