Inhomogeneous HeII reionization in Hydrodynamic Simulations. (arXiv:2002.05733v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sanderbeck_P/0/1/0/all/0/1">Phoebe Upton Sanderbeck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bird_S/0/1/0/all/0/1">Simeon Bird</a>
The reionization of the second electron of helium shapes the physical state
of intergalactic gas at redshifts between 2 < z < 5. Because performing full in
situ radiative transfer in hydrodynamic simulations is computationally
expensive for large volumes, the physics of HeII reionization is often
approximated by a uniform UV background model that does not capture the
patchiness of reionization. We have devised a model that implements the thermal
effects of HeII reionization– a way to bypass a full radiative transfer
simulation while still realizing the physics of HeII reionization that affects
observables such as the Lyman alpha forest. Here we present a
publicly-available code that flexibly models inhomogeneous HeII reionization in
simulations at a negligible computational cost. Because many of the parameters
of HeII reionization are uncertain, our model is customizable from a set of
free parameters. We show results from this code in MP-Gadget. We demonstrate
the resulting temperature evolution and temperature-density relation of
intergalactic gas– consistent with recent measurements and previous radiative
transfer simulations. We show that the impact of HeII reionization gives rise
to subtle signatures in the one-dimensional statistics of the Lyman alpha
forest at the level of several per cent, in agreement with previous findings.
The flexible nature of these simulations are ideal for studies of HeII
reionization and future observations of the HeII Lyman alpha forest.
The reionization of the second electron of helium shapes the physical state
of intergalactic gas at redshifts between 2 < z < 5. Because performing full in
situ radiative transfer in hydrodynamic simulations is computationally
expensive for large volumes, the physics of HeII reionization is often
approximated by a uniform UV background model that does not capture the
patchiness of reionization. We have devised a model that implements the thermal
effects of HeII reionization– a way to bypass a full radiative transfer
simulation while still realizing the physics of HeII reionization that affects
observables such as the Lyman alpha forest. Here we present a
publicly-available code that flexibly models inhomogeneous HeII reionization in
simulations at a negligible computational cost. Because many of the parameters
of HeII reionization are uncertain, our model is customizable from a set of
free parameters. We show results from this code in MP-Gadget. We demonstrate
the resulting temperature evolution and temperature-density relation of
intergalactic gas– consistent with recent measurements and previous radiative
transfer simulations. We show that the impact of HeII reionization gives rise
to subtle signatures in the one-dimensional statistics of the Lyman alpha
forest at the level of several per cent, in agreement with previous findings.
The flexible nature of these simulations are ideal for studies of HeII
reionization and future observations of the HeII Lyman alpha forest.
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