%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 }