AI 中文总结
GLOW项目分析近宇宙低质量星系的氧留存，发现其氧留存率为4%-25%，环境影响留存率，模拟预测值偏高，风质量负载与外流金属丰度决定留存。
AI 中文摘要
氧由恒星合成，并通过反馈驱动的外流在星系间重新分布，其当前的丰度与分布记录了恒星形成和重子循环的信息。GLOW（星系因风流失氧）项目对近宇宙中37个低质量、低金属丰度、富气体的星系（距离D<6 Mpc）的氧产生、分布与留存情况进行量化，这些星系处于恒星质量的关键范围（10^6.5 < Mstar < 10^9.5），此范围内反馈预计会强烈影响星系演化。我们结合文献结果，将分析范围扩展至10^5 < Mstar < 10^11.5。我们将从已分辨恒星得到的恒星形成历史，与ISM（星际介质）金属丰度及气体质量测量结果相结合，并将氧储量与星系际介质（CGM）的经验约束进行比较。我们发现，低质量星系留存了恒星核合成产生的氧的4%-25%（均值11%），且几乎所有留存的氧都位于气体中。当星系处于更致密环境（Theta_5>0.5）或位于大质量星系（Mstar>10^9 Msun）1 Mpc范围内时，其氧留存分数的离散度会向更高值增大，这表明环境可能影响星系留存、再循环或吸积的氧的量。与预期相反，氧留存与质量-金属丰度关系的位置无关联。尽管在CGM中检测到了电离氧，但大部分缺失的氧是位于CGM中还是已完全被逐出仍不清楚。流体动力学模拟虽成功重现了质量-金属丰度关系，但其预测的低质量星系氧留存分数远高于实测值。简单模型表明，风质量负载与外流金属丰度决定氧留存，且低质量星系相对于宇宙重子丰度吸积的重子物质更少。
英文摘要
Oxygen is forged by stars and redistributed through galaxies by feedback-driven outflows, leaving a record of star formation and the baryon cycle imprinted on its present-day abundance and distribution. The Galaxies Losing Oxygen via Winds (GLOW) project quantifies the production, distribution, and retention of oxygen in 37 low-mass, low-metallicity, gas-rich galaxies in the nearby universe (D<6 Mpc) spanning a critical stellar mass range (10^6.5<Mstar<10^9.5) where feedback is expected to strongly shape galaxy evolution. We incorporate literature results to extend the analysis over 10^5<Mstar<10^11.5. We couple star formation histories derived from resolved stars with measurements of ISM metallicity and gas mass, and compares the oxygen budgets with empirical constraints in the circumgalactic medium (CGM). We find low-mass galaxies retain between 4-25% (mean 11%) of their oxygen produced by stellar nucleosynthesis, and nearly all retained oxygen residing in the gas. Galaxies exhibit increased scatter to higher oxygen retention fractions when residing in denser environments (Theta_5>0.5) and within 1 Mpc of a massive galaxy (Mstar>10^9 Msun), indicating environment likely affects the amount of oxygen retained, recycled, or accreted to galaxies. Contrary to expectations, oxygen retention does not correlate with position on the mass-metallicity relation. Although ionized oxygen is detected in the CGM, it remains unclear whether most missing oxygen resides there or has been expelled entirely. Hydrodynamical simulations, despite successfully reproducing the mass-metallicity relation, predict much higher retention fractions than measured in low-mass galaxies. Simple modeling indicates that wind mass-loading and outflow metallicity govern oxygen retention, and that low-mass galaxies accrete less baryonic material relative to the cosmic baryon fraction.
Comments31 pages, 12 figures, 2 tables
