Reading the CARDs: The Imprint of Accretion History in the Chemical Abundances of the Milky Way's Stellar Halo
Reading the CARDs: The Imprint of Accretion History in the Chemical Abundances of the Milky Way's Stellar Halo
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DOI：
10.3847/1538-4357/ac78ea
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发表时间：
2021-10
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通讯作者：
E. Cunningham;R. Sanderson;K. Johnston;N. Panithanpaisal;M. Ness;A. Wetzel;S. Loebman;I. Escala;D. Horta;C. Faucher-Giguère
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作者：
E. Cunningham;R. Sanderson;K. Johnston;N. Panithanpaisal;M. Ness;A. Wetzel;S. Loebman;I. Escala;D. Horta;C. Faucher-Giguère
在本星系群开展大规模光谱巡天的时代，我们可以探索利用晕星的化学丰度来研究银河系（MW）和M31恒星晕的矮星系祖先的星星形成和化学富集历史。在本文中，我们调查使用化学丰度比分布（CARDs）的七个恒星晕从Latte套件的FIRE-2模拟。我们试图推断星系的组装历史建模CARD的恒星晕的Latte星系作为一个线性组合的模板CARD从破裂的矮星，不同的恒星质量M和淬火时间t 100。我们提出了一种方法来构建这些模板使用当今的矮星系。对于在这项工作中研究的七个Latte晕中的四个，我们恢复了吸积矮星的质量谱，精度<10%。对于作为t 100的函数的质量吸积分数，我们发现七个模拟中的五个的残差为20%-30%。我们讨论了这种方法的失败模式，这产生于矮星系的星星形成和化学富集历史的多样性。这些故障情况下，可以鲁棒地识别的高模型残差。虽然CARD建模方法不能成功地推断出这些情况下的组装历史，但这些破裂矮星的CARD包含了它们不寻常的形成历史的签名。我们的研究结果是有希望的使用CARDs了解更多关于MW和M31恒星晕的祖先的历史。
In the era of large-scale spectroscopic surveys in the Local Group, we can explore using chemical abundances of halo stars to study the star formation and chemical enrichment histories of the dwarf galaxy progenitors of the Milky Way (MW) and M31 stellar halos. In this paper, we investigate using the chemical abundance ratio distributions (CARDs) of seven stellar halos from the Latte suite of FIRE-2 simulations. We attempt to infer galaxies’ assembly histories by modeling the CARDs of the stellar halos of the Latte galaxies as a linear combination of template CARDs from disrupted dwarfs, with different stellar masses M ⋆ and quenching times t 100. We present a method for constructing these templates using present-day dwarf galaxies. For four of the seven Latte halos studied in this work, we recover the mass spectrum of accreted dwarfs to a precision of <10%. For the fraction of mass accreted as a function of t 100, we find the residuals of 20%–30% for five of the seven simulations. We discuss the failure modes of this method, which arise from the diversity of star formation and chemical enrichment histories that dwarf galaxies can take. These failure cases can be robustly identified by the high model residuals. Although the CARDs modeling method does not successfully infer the assembly histories in these cases, the CARDs of these disrupted dwarfs contain signatures of their unusual formation histories. Our results are promising for using CARDs to learn more about the histories of the progenitors of the MW and M31 stellar halos.