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arXiv 0801.2476astro-ph
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从z=1模拟质量-金属丰度关系

Simulating the Mass-Metallicity Relation from z=1

Mustapha Mouchine, Brad K. Gibson, Agostino Renda, Daisuke Kawata

摘要:

我们使用112 N-体/流体动力学模拟在标准的冷暗物质宇宙中,遵循星系大小的晕的形成,并调查化学富集的恒星成分和星际介质的星系,与恒星质量大于1 e9 Msun。模拟星系的化学性质与观测结果大致一致。预测的平均金属丰度和星系恒星质量的恒星和气体成分在z=0的关系与当地观察到的关系是一致的。这些关系的预测分散,这是追溯到不同的合并历史之间的模拟星系具有类似的最终质量,是类似的观察。从目前的时代到z=1,我们的模拟样本中的星系的总质量和恒星质量之间的预测相关性同意与观测。恒星质量与金属丰度的关系及其相关的散射再现的模拟结果的气体转化成恒星质量的恒星的效率不断提高,和不同的合并历史之间的星系具有类似的质量。模拟的低质量星系在z=0时的老年龄,以及大质量星系化学演化的弱水平表明,我们对超新星反馈的建模可能是不完整的,或者其他反馈过程被忽略了。(节录)

英文摘要:

We use 112 N-body/hydrodynamical simulations in the standard Cold Dark Matter universe, to follow the formation of galaxy-sized halos and investigate the chemical enrichment of both the stellar component and the interstellar medium of galaxies, with stellar masses larger than 1e9 Msun. The resulting chemical properties of the simulated galaxies are broadly consistent with the observations. The predicted relationship between the mean metallicity and the galaxy stellar mass for both the stellar and the gaseous components at z=0 are in agreement with the relationships observed locally. The predicted scatter about these relationships, which is traced to the differing merging histories amongst the simulated galaxies with similar final masses, is similar to that observed. The predicted correlations between the total mass and the stellar mass of galaxies in our simulated sample from the present epoch up to z=1 agree with observed ones. The stellar mass versus metallicity relation and its associated scatter are reproduced by the simulations as consequences of the increasing efficiency of the conversion of gas into stars with stellar mass, and the differing merging histories amongst the galaxies with similar masses. The old ages of simulated low mass galaxies at z=0, and the weak level of chemical evolution for massive galaxies suggest however that our modeling of the supernova feedback may be incomplete, or that other feedback processes have been neglected. (Abridged)

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