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arXiv 1602.07908astro-ph.GA
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半解析模型中金属富集、基本标度关系和Milky Way星系的情况

Metal enrichment in a semi-analytical model, fundamental scaling relations, and the case of Milky Way galaxies

Morgane Cousin, Véronique Buat, Samuel Boissier, Matthieu Béthermin, Yannick Roehlly, Mathieu Génois

摘要:

气流在星系形成和演化中扮演着重要的角色,为恒星形成过程提供燃料。这些机制在重元素的数量上留下了印记。因此,对这种金属丰度特征的分析为星系形成的情景提供了额外的约束。我们的目标是区分四个不同的星系形成模型的基础上两个吸积的情况下,两个不同的恒星形成食谱。我们解决的双峰吸积的情况下,一个强有力的监管恒星形成配方的影响。我们提出了一个新的扩展eGalICS模型,它允许我们跟踪金属富集过程。我们的新的化学动力学模型适用于从无金属原始吸积非常丰富的星际气体内容的情况。我们使用这个新工具来预测恒星星族和气相的金属丰度演化。我们还解决了气体金属丰度与恒星形成率(SFR)的演变。然后,我们重点关注类银河系星系的子样本。我们比较了宇宙恒星质量大会和金属富集过程的星系与观测和详细的化学演化模型。我们的模型,基于一个强大的恒星形成规则,使我们能够很好地再现恒星质量气相金属丰度关系在当地宇宙中观察到的。然而,我们观察到一个系统性的向高质量的转变。我们的$Mstar-Zg-SFR关系与最近的测量结果非常一致:我们最好的模型预测了与SFR的明显依赖性。我们的银河系类星系的SFR和金属富集的历史是一致的观测测量和详细的化学演化模型。最后,我们表明,银河系的祖先开始他们的演变低于所观察到的主序列,并逐步达到这一观察到的关系在z = 0。

英文摘要:

Gas flows play a fundamental role in galaxy formation and evolution, providing the fuel for the star formation process. These mechanisms leave an imprint in the amount of heavy elements. Thus, the analysis of this metallicity signature provides additional constraint on the galaxy formation scenario. We aim to discriminate between four different galaxy formation models based on two accretion scenarios and two different star formation recipes. We address the impact of a bimodal accretion scenario and a strongly regulated star formation recipe. We present a new extension of the eGalICS model, which allows us to track the metal enrichment process. Our new chemodynamical model is applicable for situations ranging from metal-free primordial accretion to very enriched interstellar gas contents. We use this new tool to predict the metallicity evolution of both the stellar populations and gas phase. We also address the evolution of the gas metallicity with the star formation rate (SFR). We then focus on a sub-sample of Milky Way-like galaxies. We compare both the cosmic stellar mass assembly and the metal enrichment process of such galaxies with observations and detailed chemical evolution models. Our models, based on a strong star formation regulation, allow us to reproduce well the stellar mass to gas-phase metallicity relation observed in the local universe. However, we observe a systematic shift towards high masses. Our $Mstar-Zg-SFR relation is in good agreement with recent measurements: our best model predicts a clear dependence with the SFR. Both SFR and metal enrichment histories of our Milky Way-like galaxies are consistent with observational measurements and detailed chemical evolution models. We finally show that Milky Way progenitors start their evolution below the observed main sequence and progressively reach this observed relation at z = 0.

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