论文标题
恒星形成星系中气体积聚的证据：异常高金属性区域中的N/O高丰度
Evidence for the Accretion of Gas in Star-Forming Galaxies: High N/O Abundances in Regions of Anomalously-Low Metallicity
论文作者
论文摘要
尽管所有用于星系进化的模型都需要通过持续的恒星形成来维持其生长，但事实证明，它很难直接检测到这种流入的材料。在本文中，我们使用附近的恒星形成星系在Apache Point天文台（漫画）调查的SDSS IV映射中的数据来寻找印在星际介质化学成分的增生证据。我们在先前识别为O/H值的区域中测量O/H和N/O的丰度比。我们表明，N/O与O/H平面中这些区域的异常位置表明，它们是通过混合具有较高金属性的磁盘气体与具有较低金属性的积聚气体的混合而产生的。与先前对这些异常低金属性区域的分析一起，这些结果表明，金属贫困气体的积聚可能可以在当今的晚期星系中维持恒星形成。
While all models for the evolution of galaxies require the accretion of gas to sustain their growth via on-going star formation, it has proven difficult to directly detect this inflowing material. In this paper we use data of nearby star-forming galaxies in the SDSS IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to search for evidence of accretion imprinted in the chemical composition of the interstellar medium. We measure both the O/H and N/O abundance ratios in regions previously identified as having anomalously low values of O/H. We show that the unusual locations of these regions in the N/O vs. O/H plane indicate that they have been created through the mixing of disk gas having higher metallicity with accreted gas having lower metallicity. Taken together with previous analysis on these anomalously low-metallicity regions, these results imply that accretion of metal-poor gas can probably sustain star formation in present-day late-type galaxies.
