Stellar feedback and bulge formation in clumpy discs
Stellar feedback and bulge formation in clumpy discs
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DOI：
10.1111/j.1365-2966.2012.21981.x
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发表时间：
2011-11
影响因子：
4.8
通讯作者：
P. Hopkins;D. Keres̆;N. Murray;E. Quataert;Lars Hernquist Berkeley;Cita;Harvard
中科院分区：
文献类型：
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作者：
P. Hopkins;D. Keres̆;N. Murray;E. Quataert;Lars Hernquist Berkeley;Cita;Harvard
我们利用孤立星系的数值模拟研究恒星反馈对高红移、富含气体的星系中巨大恒星形成气体“团块”的形成和演化的影响。这样的星系盘是不稳定的，形成了富含气体的团块，这些团块的性质最初只取决于全球盘的性质，而不是反馈的微观物理。在没有恒星反馈的模拟中，团块将其质量的一个单位阶分数转化为恒星并下沉到中心，形成一个巨大的凸起，并将大多数恒星踢到一个更扩展的恒星包络中。相比之下，即使是最大质量的团块，在1000万年至10000万年的时间尺度内，当它们将质量的10%至20%转化为恒星时，强烈的辐射恒星反馈也会扰乱它们，将一些物质喷射到超级风中，并将其余的气体再循环到弥漫星际介质（ISM）中。这抑制了几个因素的直接“团块聚结”的隆起形成率。然而，在没有合并的情况下，星系盘确实经历了显着的内部演化：团块的形成和连续的分裂，并将气体扭向星系中心。由此产生的演变是定性类似的酒吧/螺旋演变模拟更均匀的ISM。
We use numerical simulations of isolated galaxies to study the effects of stellar feedback on the formation and evolution of giant star-forming gas ‘clumps’ in high-redshift, gas-rich galaxies. Such galactic discs are unstable to the formation of bound gas-rich clumps whose properties initially depend only on global disc properties, not the microphysics of feedback. In simulations without stellar feedback, clumps turn an order-unity fraction of their mass into stars and sink to the centre, forming a large bulge and kicking most of the stars out into a much more extended stellar envelope. By contrast, strong radiative stellar feedback disrupts even the most massive clumps after they turn ∼10–20 per cent of their mass into stars, in a time-scale of ∼10–100 Myr, ejecting some material into a superwind and recycling the rest of the gas into the diffuse interstellar medium (ISM). This suppresses the bulge formation rate by direct ‘clump coalescence’ by a factor of several. However, the galactic discs do undergo significant internal evolution in the absence of mergers: clumps form and disrupt continuously and torque gas to the galactic centre. The resulting evolution is qualitatively similar to bar/spiral evolution in simulations with a more homogeneous ISM.