The Physical Nature of the Most Metal-Poor Damped Lyman Alpha Systems
S. Yuan, и R. Cen. (2015)cite arxiv:1511.07060Comment: 13 pages, 9 figures. Submitted to MNRAS in July 2015.
Аннотация
Utilizing the high-resolution, large-scale LAOZI cosmological simulations we
investigate the nature of the metal-poor ($Z/H<-2$) damped Lyman alpha
systems (mpDLA) at $z=3$. The following physical picture of mpDLAs emerges. The
majority of mpDLAs inhabit regions $20$~kpc from the host galaxy center on
infalling cold gas streams originating from the intergalactic medium, with
infall velocity of $100$ km/s and temperature of $10^4$ K. For each
host galaxy, on average, about $1\%$ of the area within a radius $150$~kpc is
covered by mpDLAs. The mpDLAs are relatively diffuse ($n_gas \sim
10^-2$ cm$^-3$), Jeans quasi-stable, and have very low star formation rate
($\Sigma 10^-4 \ yr^-1 \ kpc^-2$). As mpDLAs
migrate inward to the galaxy center, they mix with high metallicity gas and
stellar outflows in the process, removing themselves from the metal-poor
category and rendering the central ($5$ kpc) regions of galaxies devoid of
mpDLAs. Thus, the central regions of the host galaxies are populated by mostly
metal-rich DLAs instead of mpDLAs. All observables of the simulated mpDLAs are
in excellent agreement with observations, except the gas density, which is
about a factor of ten lower than the value inferred observationally. However,
the observationally inferred value is based on simplified assumptions that are
not borne out in the simulations.
Описание
[1511.07060] The Physical Nature of the Most Metal-Poor Damped Lyman Alpha Systems
%0 Generic
%1 yuan2015physical
%A Yuan, Sihan
%A Cen, Renyue
%D 2015
%K dla metal poor simulation
%T The Physical Nature of the Most Metal-Poor Damped Lyman Alpha Systems
%U http://arxiv.org/abs/1511.07060
%X Utilizing the high-resolution, large-scale LAOZI cosmological simulations we
investigate the nature of the metal-poor ($Z/H<-2$) damped Lyman alpha
systems (mpDLA) at $z=3$. The following physical picture of mpDLAs emerges. The
majority of mpDLAs inhabit regions $20$~kpc from the host galaxy center on
infalling cold gas streams originating from the intergalactic medium, with
infall velocity of $100$ km/s and temperature of $10^4$ K. For each
host galaxy, on average, about $1\%$ of the area within a radius $150$~kpc is
covered by mpDLAs. The mpDLAs are relatively diffuse ($n_gas \sim
10^-2$ cm$^-3$), Jeans quasi-stable, and have very low star formation rate
($\Sigma 10^-4 \ yr^-1 \ kpc^-2$). As mpDLAs
migrate inward to the galaxy center, they mix with high metallicity gas and
stellar outflows in the process, removing themselves from the metal-poor
category and rendering the central ($5$ kpc) regions of galaxies devoid of
mpDLAs. Thus, the central regions of the host galaxies are populated by mostly
metal-rich DLAs instead of mpDLAs. All observables of the simulated mpDLAs are
in excellent agreement with observations, except the gas density, which is
about a factor of ten lower than the value inferred observationally. However,
the observationally inferred value is based on simplified assumptions that are
not borne out in the simulations.
@misc{yuan2015physical,
abstract = {Utilizing the high-resolution, large-scale LAOZI cosmological simulations we
investigate the nature of the metal-poor (${\rm [Z/H]<-2}$) damped Lyman alpha
systems (mpDLA) at $z=3$. The following physical picture of mpDLAs emerges. The
majority of mpDLAs inhabit regions $\ge 20$~kpc from the host galaxy center on
infalling cold gas streams originating from the intergalactic medium, with
infall velocity of $\sim 100$ km/s and temperature of $\sim 10^{4}$ K. For each
host galaxy, on average, about $1\%$ of the area within a radius $150$~kpc is
covered by mpDLAs. The mpDLAs are relatively diffuse ($n_{\rm{gas}} \sim
10^{-2}$ cm$^{-3}$), Jeans quasi-stable, and have very low star formation rate
($\dot{\Sigma} \le 10^{-4} \msun \rm{\ yr}^{-1} \rm{\ kpc}^{-2}$). As mpDLAs
migrate inward to the galaxy center, they mix with high metallicity gas and
stellar outflows in the process, removing themselves from the metal-poor
category and rendering the central ($\le 5$ kpc) regions of galaxies devoid of
mpDLAs. Thus, the central regions of the host galaxies are populated by mostly
metal-rich DLAs instead of mpDLAs. All observables of the simulated mpDLAs are
in excellent agreement with observations, except the gas density, which is
about a factor of ten lower than the value inferred observationally. However,
the observationally inferred value is based on simplified assumptions that are
not borne out in the simulations.},
added-at = {2015-11-24T10:03:35.000+0100},
author = {Yuan, Sihan and Cen, Renyue},
biburl = {https://www.bibsonomy.org/bibtex/2b2b97b9be46f40c8e1322e736775cf80/miki},
description = {[1511.07060] The Physical Nature of the Most Metal-Poor Damped Lyman Alpha Systems},
interhash = {3ec8043b29df1076147c80c5c6e1c57b},
intrahash = {b2b97b9be46f40c8e1322e736775cf80},
keywords = {dla metal poor simulation},
note = {cite arxiv:1511.07060Comment: 13 pages, 9 figures. Submitted to MNRAS in July 2015},
timestamp = {2015-11-24T10:03:35.000+0100},
title = {The Physical Nature of the Most Metal-Poor Damped Lyman Alpha Systems},
url = {http://arxiv.org/abs/1511.07060},
year = 2015
}