TwO Parameters Semi Empirical Model (TOPSEM): Galaxy Evolution and Bulge/Disk Dicothomy from Two-stage Halo Accretion
TwO Parameters Semi Empirical Model (TOPSEM): Galaxy Evolution and Bulge/Disk Dicothomy from Two-stage Halo Accretion
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DOI：
10.3847/1538-4357/ace76d
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发表时间：
2023-08
期刊：
影响因子：
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通讯作者：
L. Boco;A. Lapi;F. Shankar;H. Fu;F. Gabrielli;A. Sicilia
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文献类型：
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作者：
L. Boco;A. Lapi;F. Shankar;H. Fu;F. Gabrielli;A. Sicilia
近年来，人们越来越多地关注半经验的数据驱动模型，以解决星系形成和演化这一复杂且仍有很大争议的话题的某些方面。本文提出了一个新的半经验模型，它的特点是简单：它只依赖于两个假设，一个初始条件和两个自由参数。星系晕通过比晕吸积率（sHAR）和比星星形成率（sSFR）之间的丰度匹配与演化中的暗物质晕相联系。淬火单独处理，在一个完全经验的方式，边缘化静止的星系和测试我们的假设上的sSFR演变无污染的被动对象。我们的灵活和透明的模型是能够再现所观察到的恒星质量函数z ≤ 5，支持我们的假设sHAR和sSFR之间的单调关系。然后，我们利用该模型来测试星系形态演化的假设。我们试图解释两个晕吸积模式：快速和缓慢吸积的隆起/磁盘双峰。具体来说，我们推测，凸起/球状组件可能形成在早期阶段的快速晕增长，而磁盘形成在后期阶段的缓慢吸积。我们发现与观测的凸起和椭圆质量函数非常一致。
In recent years, increasing attention has been devoted to semi-empirical, data-driven models to tackle some aspects of the complex and still largely debated topic of galaxy formation and evolution. We here present a new semi-empirical model whose marking feature is simplicity: it relies on solely two assumptions, one initial condition and two free parameters. Galaxies are connected to evolving dark matter haloes through abundance matching between specific halo accretion rate (sHAR) and specific star formation rate (sSFR). Quenching is treated separately, in a fully empirical way, to marginalize over quiescent galaxies and test our assumption on the sSFR evolution without contaminations from passive objects. Our flexible and transparent model is able to reproduce the observed stellar mass functions up to z ∼ 5, giving support to our hypothesis of a monotonic relation between sHAR and sSFR. We then exploit the model to test a hypothesis on morphological evolution of galaxies. We attempt to explain the bulge/disk bimodality in terms of the two halo accretion modes: fast and slow accretion. Specifically, we speculate that bulge/spheroidal components might form during the early phase of fast halo growth, while disks form during the later phase of slow accretion. We find excellent agreement with both the observational bulge and elliptical mass functions.