由气体吸积驱动的银河系化学富集历史的中断
The disrupted chemical enrichment history of the Milky Way driven by gas accretion
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中文总结 AI 辅助
研究利用APOGEE巡天数据校正后测量银河系时间分辨的星系尺度平均金属丰度，发现其当前金属丰度接近太阳，年龄-金属丰度关系中断、质量-金属丰度图演化轨迹受扰，揭示气体吸积对银河系化学富集历史的关键影响。
中文摘要 AI 辅助
作为唯一能从内部有利位置进行时间分辨观测的星系，银河系为了解星系化学富集历史、建立基本比例关系以及潜在天体物理过程提供了独特见解。但这种内部视角也引入了强烈选择效应。我们利用APOGEE巡天数据，经选择函数校正后测量了银河系时间分辨的星系尺度平均金属丰度。结果揭示了银河系当前金属丰度接近太阳，积分年龄-金属丰度关系中断，质量-金属丰度图中演化轨迹受干扰，可能是约70亿年前外部气体吸积导致的稀释和由内向外生长所致。结果凸显了气体吸积在扰乱星系富集历史及引入质量-金属丰度关系散射方面的关键作用。
英文摘要
As the only galaxy enabling temporally-resolved observations from an internal vantage point, the Milky Way as a galaxy offers unique insights into galactic chemical enrichment history, establishment of fundamental scaling relations, and the underlying astrophysical processes. However, this insider perspective also introduces strong selection effects, hindering direct measurement of the Milky Way's global properties and comparison with the broader galaxy population, for the vast majority of which only integrated properties can be measured. {Here we report our measurements of the Milky Way's temporally-resolved galaxy-scale average metallicity using data from the APOGEE survey after correction for the selection function. Our findings unveil a present-day metallicity of the Milky Way close to the Sun, an interrupted integrated age-metallicity relation, and a disturbed evolutionary trajectory in the mass-metallicity diagram, likely caused by dilution and inside-out growth associated with external gas accretion around 7~Gyr ago. Our results highlight the critical role of gas accretion in disrupting the galactic enrichment histories and introducing scatter in mass-metallicity relations.
