We present a post-processing tool for GADGET-2 simulations to model various
observed properties of the Ly$\alpha$ forest at $2 z 4$ that enables
an efficient parameter estimation. In particular, we model the thermal and
ionization histories that are not computed self-consistently by default in
GADGET-2. We capture the effect of pressure smoothing by running GADGET-2 at an
elevated temperature floor and using an appropriate smoothing kernel. We
validate our procedure by comparing different statistics derived from our
method with those derived using self-consistent simulations with GADGET-3.
These statistics are: line of sight density field power spectrum (PS), flux
probability distribution function (PDF), flux PS, wavelet statistics, curvature
statistics, HI column density ($N_HI$) distribution function, linewidth
($b$) distribution and $b$ versus $N_HI$ scatter. For the
temperature floor of $10^4$ K and typical signal-to-noise of 25, the results
agree well within $1\sigma$ level. Moreover for a given cosmology, we gain a
factor of $N$ in computing time for modelling the intergalactic medium
under $N 1$ different thermal histories. In addition, our method allows us
to simulate the non-equilibrium evolution of thermal and ionization state of
the gas and include heating due to non-standard sources like cosmic rays and
high energy $\gamma$-rays from Blazars.
Description
[1705.05374] Efficient hydrodynamical simulations of the high-redshift intergalactic medium
%0 Generic
%1 gaikwad2017efficient
%A Gaikwad, Prakash
%A Choudhury, Tirthankar Roy
%A Srianand, Raghunathan
%A Khaire, Vikram
%D 2017
%K history igm simulations thermal
%T Efficient hydrodynamical simulations of the high-redshift intergalactic
medium
%U http://arxiv.org/abs/1705.05374
%X We present a post-processing tool for GADGET-2 simulations to model various
observed properties of the Ly$\alpha$ forest at $2 z 4$ that enables
an efficient parameter estimation. In particular, we model the thermal and
ionization histories that are not computed self-consistently by default in
GADGET-2. We capture the effect of pressure smoothing by running GADGET-2 at an
elevated temperature floor and using an appropriate smoothing kernel. We
validate our procedure by comparing different statistics derived from our
method with those derived using self-consistent simulations with GADGET-3.
These statistics are: line of sight density field power spectrum (PS), flux
probability distribution function (PDF), flux PS, wavelet statistics, curvature
statistics, HI column density ($N_HI$) distribution function, linewidth
($b$) distribution and $b$ versus $N_HI$ scatter. For the
temperature floor of $10^4$ K and typical signal-to-noise of 25, the results
agree well within $1\sigma$ level. Moreover for a given cosmology, we gain a
factor of $N$ in computing time for modelling the intergalactic medium
under $N 1$ different thermal histories. In addition, our method allows us
to simulate the non-equilibrium evolution of thermal and ionization state of
the gas and include heating due to non-standard sources like cosmic rays and
high energy $\gamma$-rays from Blazars.
@misc{gaikwad2017efficient,
abstract = {We present a post-processing tool for GADGET-2 simulations to model various
observed properties of the Ly$\alpha$ forest at $2 \leq z \leq 4$ that enables
an efficient parameter estimation. In particular, we model the thermal and
ionization histories that are not computed self-consistently by default in
GADGET-2. We capture the effect of pressure smoothing by running GADGET-2 at an
elevated temperature floor and using an appropriate smoothing kernel. We
validate our procedure by comparing different statistics derived from our
method with those derived using self-consistent simulations with GADGET-3.
These statistics are: line of sight density field power spectrum (PS), flux
probability distribution function (PDF), flux PS, wavelet statistics, curvature
statistics, HI column density (${\rm N_{HI}}$) distribution function, linewidth
($b$) distribution and $b$ versus $\log {\rm N_{HI}}$ scatter. For the
temperature floor of $10^4$ K and typical signal-to-noise of 25, the results
agree well within $1\sigma$ level. Moreover for a given cosmology, we gain a
factor of $\sim N$ in computing time for modelling the intergalactic medium
under $N \gg 1$ different thermal histories. In addition, our method allows us
to simulate the non-equilibrium evolution of thermal and ionization state of
the gas and include heating due to non-standard sources like cosmic rays and
high energy $\gamma$-rays from Blazars.},
added-at = {2017-05-17T10:02:36.000+0200},
author = {Gaikwad, Prakash and Choudhury, Tirthankar Roy and Srianand, Raghunathan and Khaire, Vikram},
biburl = {https://www.bibsonomy.org/bibtex/26c4c003c63b4f68aa5ef75fdae917437/miki},
description = {[1705.05374] Efficient hydrodynamical simulations of the high-redshift intergalactic medium},
interhash = {06b213cf5c14dffc5f48864ed5539163},
intrahash = {6c4c003c63b4f68aa5ef75fdae917437},
keywords = {history igm simulations thermal},
note = {cite arxiv:1705.05374Comment: 21 pages, 14 figures, 3 tables. submitted to MNRAS},
timestamp = {2017-05-17T10:02:36.000+0200},
title = {Efficient hydrodynamical simulations of the high-redshift intergalactic
medium},
url = {http://arxiv.org/abs/1705.05374},
year = 2017
}