作为恒星形成燃料的被包裹的恒星喷出物和星系质量-金属丰度关系起源的意义
Recycled stellar ejecta as fuel for star formation and implications for the origin of the galaxy mass-metallicity relation
摘要：
我们使用的EAGLE和OWLS项目的宇宙学，流体动力学模拟，以评估回收的恒星喷出物作为恒星形成的燃料的意义。恒星质量损失对宇宙恒星形成率（SFR）和恒星质量密度的贡献率随时间增加，在$z=0$处分别达到$35 \%$和$19 \%$。对于$M_{\ast} < 10^{10.5}$ M $_{\odot}$，再循环的重要性随着星系恒星质量的增加而急剧增加，并在更高的质量下温和地降低。这种趋势源于与恒星形成和活动星系核相关的反馈的质量依赖性，它优先抑制了由再循环提供燃料的恒星形成。再循环对卫星比中心更重要，其贡献随银河中心半径的增加而减小。AGB星的相对贡献随时间和朝向星系中心而增加。这是AGB喷出物比大质量恒星更缓慢释放的结果，并且后者被恒星形成驱动的外流和被锁定在恒星残余物中优先移除。回收燃料的恒星形成表现出紧密的，正相关的星系金属丰度，与第二次依赖的相对丰度的α元素（主要是在大质量恒星合成），这是不敏感的次网格模型的反馈。因此，我们的结论是直接相关的质量金属丰度关系和金属丰度梯度的起源。将回收和金属丰度之间的关系应用到所观察到的质量-金属丰度关系中，得到了回收的质量相关贡献的最佳估计。对于质量与银河系相似的中心，我们推断回收的恒星喷出物对SFR和恒星质量的贡献分别为$35 \%$和$20 \%$。
英文摘要：
We use cosmological, hydrodynamical simulations from the EAGLE and OWLS projects to assess the significance of recycled stellar ejecta as fuel for star formation. The fractional contributions of stellar mass loss to the cosmic star formation rate (SFR) and stellar mass densities increase with time, reaching $35 \%$ and $19 \%$, respectively, at $z=0$. The importance of recycling increases steeply with galaxy stellar mass for $M_{\ast} < 10^{10.5}$ M$_{\odot}$, and decreases mildly at higher mass. This trend arises from the mass dependence of feedback associated with star formation and AGN, which preferentially suppresses star formation fuelled by recycling. Recycling is more important for satellites than centrals and its contribution decreases with galactocentric radius. The relative contribution of AGB stars increases with time and towards galaxy centers. This is a consequence of the more gradual release of AGB ejecta compared to that of massive stars, and the preferential removal of the latter by star formation-driven outflows and by lock up in stellar remnants. Recycling-fuelled star formation exhibits a tight, positive correlation with galaxy metallicity, with a secondary dependence on the relative abundance of alpha elements (which are predominantly synthesized in massive stars), that is insensitive to the subgrid models for feedback. Hence, our conclusions are directly relevant for the origin of the mass-metallicity relation and metallicity gradients. Applying the relation between recycling and metallicity to the observed mass-metallicity relation yields our best estimate of the mass-dependent contribution of recycling. For centrals with a mass similar to that of the Milky Way, we infer the contributions of recycled stellar ejecta to the SFR and stellar mass to be $35 \%$ and $20 \%$, respectively.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
