论文标题
失控的星星如何增强银河流出
How runaway stars boost galactic outflows
论文作者
论文摘要
在以超新星的身份结束生命之前，大约有10％的OB星星被踢出了出生的簇。这些所谓的失控恒星可以将数百个parsec传播到低密度的星际介质中，那里有效地沉积了恒星反馈的动量和能量。在这项工作中，我们探讨了这种机制如何影响星系的大规模特性，例如流出。为此，我们使用了一种新模型，该模型以星级的方式对待OB恒星及其相关的反馈过程。通过此模型，我们比较了两个类似银河系的星系的流体动力学模拟，一个我们包括runaways，一个我们忽略了它们。包括失控的恒星在气体密度范围为1e-5 cm^-3至1e-3 cm^-3的区域中导致了两倍的超新星爆炸。这会导致臂间区域的更有效加热，并驱动强烈的银河风，其质量负载因子最多可提高一个数量级。这些流出产生了更大，更扩展的多相呈周围培养基，以及光环中的茂密云。相反，由于在致密的恒星形成区域中释放了较少的能量和动量，因此星际介质的冷阶段对反馈效应的干扰较少。
Roughly ten per cent of OB stars are kicked out of their natal clusters before ending their life as supernovae. These so-called runaway stars can travel hundreds of parsecs into the low-density interstellar medium, where momentum and energy from stellar feedback is efficiently deposited. In this work we explore how this mechanism affects large scale properties of the galaxy, such as outflows. To do so we use a new model which treats OB stars and their associated feedback processes on a star-by-star basis. With this model we compare two hydrodynamical simulations of Milky Way-like galaxies, one where we include runaways, and one where we ignore them. Including runaway stars leads to twice as many supernovae explosions in regions with gas densities ranging from 1e-5 cm^-3 to 1e-3 cm^-3. This results in more efficient heating of the inter-arm regions, and drives strong galactic winds with mass loading factors boosted by up to one order of magnitude. These outflows produce a more massive and extended multi-phase circumgalactic medium, as well as a population of dense clouds in the halo. Conversely, since less energy and momentum is released in the dense star forming regions, the cold phase of the interstellar medium is less disturbed by feedback effects.
