On the model of the circumgalactic mist: the implications of cloud sizes
in galactic winds and halos
C. Liang, и I. Remming. (2018)cite arxiv:1806.10688Comment: Submitted to MNRAS, comments welcome.
Аннотация
Ubiquitous detections of cold/warm gas around galaxies indicate that the
circumgalactic medium (CGM) is multiphase and dynamic. Recent state-of-the-art
cosmological galaxy simulations have generally underproduced the column density
of cold halo gas. We argue that this may be due to a mismatch of spatial
resolution in the circumgalactic space and the relevant physical scales at
which the cold gas operates. Using semi-analytic calculations and a set of
magnetohydrodynamic (MHD) simulations, we present a multiphase model of the
gaseous halos around galaxies, the circumgalactic mist (CGm). The CGm model is
based on the idea that the observed cold halo gas may be a composite of cold,
dense and small cloudlets embedded in a hot diffuse halo, resembling
terrestrial clouds and mist. We show that the resulting cold gas from thermal
instabilities conforms to a characteristic column density of $N_H\approx
10^17cm^-2$ as predicted by the $c_s t_cool$ ansatz. The model
implies a large number of cold clumps in the inner galactic halo with a small
volume filling factor but large covering fraction. The model also naturally
gives rise to spatial extents and differential covering fractions of cold, warm
and hot gas. To self-consistently model the co-evolution of the CGM and star
formation within galaxies, future simulations must address the mismatch of the
spatial resolution and characteristic scale of cold gas.
Описание
[1806.10688] On the model of the circumgalactic mist: the implications of cloud sizes in galactic winds and halos
%0 Generic
%1 liang2018model
%A Liang, Cameron J.
%A Remming, Ian S.
%D 2018
%K cgm cloud simulations small
%T On the model of the circumgalactic mist: the implications of cloud sizes
in galactic winds and halos
%U http://arxiv.org/abs/1806.10688
%X Ubiquitous detections of cold/warm gas around galaxies indicate that the
circumgalactic medium (CGM) is multiphase and dynamic. Recent state-of-the-art
cosmological galaxy simulations have generally underproduced the column density
of cold halo gas. We argue that this may be due to a mismatch of spatial
resolution in the circumgalactic space and the relevant physical scales at
which the cold gas operates. Using semi-analytic calculations and a set of
magnetohydrodynamic (MHD) simulations, we present a multiphase model of the
gaseous halos around galaxies, the circumgalactic mist (CGm). The CGm model is
based on the idea that the observed cold halo gas may be a composite of cold,
dense and small cloudlets embedded in a hot diffuse halo, resembling
terrestrial clouds and mist. We show that the resulting cold gas from thermal
instabilities conforms to a characteristic column density of $N_H\approx
10^17cm^-2$ as predicted by the $c_s t_cool$ ansatz. The model
implies a large number of cold clumps in the inner galactic halo with a small
volume filling factor but large covering fraction. The model also naturally
gives rise to spatial extents and differential covering fractions of cold, warm
and hot gas. To self-consistently model the co-evolution of the CGM and star
formation within galaxies, future simulations must address the mismatch of the
spatial resolution and characteristic scale of cold gas.
@misc{liang2018model,
abstract = {Ubiquitous detections of cold/warm gas around galaxies indicate that the
circumgalactic medium (CGM) is multiphase and dynamic. Recent state-of-the-art
cosmological galaxy simulations have generally underproduced the column density
of cold halo gas. We argue that this may be due to a mismatch of spatial
resolution in the circumgalactic space and the relevant physical scales at
which the cold gas operates. Using semi-analytic calculations and a set of
magnetohydrodynamic (MHD) simulations, we present a multiphase model of the
gaseous halos around galaxies, the circumgalactic mist (CGm). The CGm model is
based on the idea that the observed cold halo gas may be a composite of cold,
dense and small cloudlets embedded in a hot diffuse halo, resembling
terrestrial clouds and mist. We show that the resulting cold gas from thermal
instabilities conforms to a characteristic column density of $N_{\rm H}\approx
10^{17}\rm{cm^{-2}}$ as predicted by the $c_s t_{\rm cool}$ ansatz. The model
implies a large number of cold clumps in the inner galactic halo with a small
volume filling factor but large covering fraction. The model also naturally
gives rise to spatial extents and differential covering fractions of cold, warm
and hot gas. To self-consistently model the co-evolution of the CGM and star
formation within galaxies, future simulations must address the mismatch of the
spatial resolution and characteristic scale of cold gas.},
added-at = {2018-06-29T12:47:09.000+0200},
author = {Liang, Cameron J. and Remming, Ian S.},
biburl = {https://www.bibsonomy.org/bibtex/2c48eaf2d8a4531e8a84bba5e8908bfd8/miki},
description = {[1806.10688] On the model of the circumgalactic mist: the implications of cloud sizes in galactic winds and halos},
interhash = {485a61a61f97a9675c9915a8ada57cf1},
intrahash = {c48eaf2d8a4531e8a84bba5e8908bfd8},
keywords = {cgm cloud simulations small},
note = {cite arxiv:1806.10688Comment: Submitted to MNRAS, comments welcome},
timestamp = {2018-06-29T12:47:09.000+0200},
title = {On the model of the circumgalactic mist: the implications of cloud sizes
in galactic winds and halos},
url = {http://arxiv.org/abs/1806.10688},
year = 2018
}