标题： 第一颗恒星对白矮星亮度函数 faint 端的影响 显示英文标题

标题： The imprint of the first stars on the faint end of the white dwarf luminosity function

摘要： 第三星族恒星因其被认为形成于早期宇宙的原始气体且具有极低的金属丰度而被特征化。尽管第三星族恒星的存在已被广泛接受，但缺乏直接观测证据阻碍了对其性质的研究。本文中，我们探讨了利用这些古老恒星遗迹——白矮星的亮度函数来限制其性质的可能性。我们通过使用半解析模型A-SLOTH模拟类似银河系的星系中的恒星形成过程，研究白矮星种群的形成与演化。我们应用线性初-终质量关系和Mestel冷却模型来推导白矮星的亮度函数。所得亮度函数总体上与可用的观测和理论预测一致——在Mabs = 16处有一个指数增长到最大值，并在Mabs > 16时突然下降。我们探索了模型的不确定性并与观测估计进行了比较。我们采用两种不同的第三星族恒星初始质量函数模型，表明亮度函数的暗端印记了第三星族遗迹的特征。如果未来观测中检测到这一特征，它将为第三星族恒星提供线索，同时也将是低至中等质量第三星族恒星的间接证据。我们讨论了检测这些特征的挑战与前景。 显示英文摘要

摘要： Population III stars are characterized by extremely low metallicities as they are thought to be formed from a pristine gas in the early Universe. Although the existence of Population III stars is widely accepted, the lack of direct observational evidence hampers the study of the nature of the putative stars. In this article, we explore the possibilities of constraining the nature of the oldest stars by using the luminosity function of their remnants -- white dwarfs. We study the formation and evolution of white dwarf populations by following star formation in a Milky Way-like galaxy using the semi-analytic model A-SLOTH. We derive the white dwarf luminosity function by applying a linear Initial-Final Mass Relation and Mestel's cooling model. The obtained luminosity function is generally in agreement with available observations and theoretical predictions -- with an exponential increase to a maximum of Mabs = 16 and a sudden drop for Mabs > 16. We explore the uncertainties of our model and compare them to the observational estimates. We adopt two different models of the initial mass function of Population III stars to show that the faint end of the luminosity function imprints the signature of Population III remnants. If the feature is detected in future observations, it would provide a clue to Population III stars and would also be an indirect evidence of low- to intermediate-mass Population III stars. We discuss the challenges and prospects for detecting the signatures.