高红移富气星系中巨团的长寿命和外流的诞生
The long lives of giant clumps and the birth of outflows in gas-rich galaxies at high redshift
摘要：
在高红移的恒星形成盘星系经常受到剧烈的盘不稳定性的影响，其特征是巨大的团块，其命运尚未被理解。主要的问题是，这些团块是否会像今天星系中的分子云一样，在其动力学时间尺度（<5000万年）内分裂，或者它们是否会在超过一个圆盘轨道时间（~ 30000万年）的恒星反馈中幸存下来，在这种情况下，它们可以向内迁移并帮助建立中央隆起。我们提出了高红移盘的3.5- 7 pc分辨率AMR模拟，包括光电离，辐射压力和超新星反馈（Renaud等人，2013年，Perret等人，这一天体-pH问题）。我们的辐射压力模型从基本物理原理确定了风的质量负荷和初始速度。我们发现，巨大的团块产生稳定的流出率相当，有时略大于他们的恒星形成率，速度基本上足以逃离星系。团簇也会因为潮汐剥离而失去质量，特别是年老的恒星，因此团簇中的恒星星族仍然相对年轻（<= 2亿年）。这些团块在气体外流和恒星损失中幸存下来，因为它们在富含气体的湍流盘中徘徊，它们可以以高速率重新吸积气体，以补偿外流和潮汐剥离，总体上保持现实和自我调节的气体和恒星质量。我们的模拟产生的气体流出的速度，密度和质量负载与观测一致，并在同一时间表明，巨大的团块生存数百万年，并完成迁移到高红移星系的中心，没有快速分散和重组的团块。
英文摘要：
Star-forming disk galaxies at high redshift are often subject to violent disk instability, characterized by giant clumps whose fate is yet to be understood. The main question is whether the clumps disrupt within their dynamical timescale (<50Myr), like molecular clouds in today's galaxies, or whether they survive stellar feedback for more than a disk orbital time (~300Myr) in which case they can migrate inward and help building the central bulge. We present 3.5-7pc resolution AMR simulations of high-redshift disks including photo-ionization, radiation pressure, and supernovae feedback (Renaud et al. 2013, and Perret et al., this astro-ph issue). Our modeling of radiation pressure determines the mass loading and initial velocity of winds from basic physical principles. We find that the giant clumps produce steady outflow rates comparable to and sometimes somewhat larger than their star formation rate, with velocities largely sufficient to escape galaxy. The clumps also lose mass, especially old stars, by tidal stripping, and the stellar populations contained in the clumps hence remain relatively young (<=200Myr), as observed. The clumps survive gaseous outflows and stellar loss, because they are wandering in gas-rich turbulent disks from which they can re-accrete gas at high rates compensating for outflows and tidal stripping, overall keeping realistic and self-regulated gaseous and stellar masses. Our simulations produce gaseous outflows with velocities, densities and mass loading consistent with observations, and at the same time suggest that the giant clumps survive for hundreds of Myr and complete their migration to the center of high-redshift galaxies, without rapid dispersion and reformation of clumps.
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