论文标题
银河系中的冷模式和热模式积聚：熵方法
Cold-mode and hot-mode accretion in galaxy formation: an entropy approach
论文作者
论文摘要
我们已经用$ M _ {\ rm vir} \ sim 10^{12} {\ rm \，m} _ \ odot $分析了两个宇宙变焦模拟，无论是带有反馈和反馈。我们表明，基于基础层间培养基状态方程的熵标准可以成功地分离冷模式积聚。冲击加热的气体具有不可忽略的湍流支持，并且冷却效率低下。在没有反馈的模拟中，只有一小部分（$ \ sim 20 $ 20 $）来自恒星质量，这些质量来自热圆形培养基，尽管由于我们的小数字统计，应谨慎得出定量结论。有了反馈，由于超新星加热的气体重新加热，因此比例更大，与吸积冲击加热的气体相比，熵的距离较低，冷却时间较短。我们已经将Nihao的结果与Galics 2.1半分析模型的结果进行了比较。 Galics 2.1中实施的冲击稳定性标准成功地重现了从冷模型到热模式的过渡。
We have analysed two cosmological zoom simulations with $M_{\rm vir}\sim 10^{12}{\rm\,M}_\odot$ from the NIHAO series, both with and without feedback. We show that an entropy criterion based on the equation of state of the intergalactic medium can successfully separate cold- and hot-mode accretion. The shock-heated gas has non-negligible turbulent support and cools inefficiently. In the simulations without feedback, only a small fraction ($\sim 20$ per cent) of the stellar mass comes from baryons that have been in the hot circumgalactic medium, although quantitative conclusions should be taken with caution due to our small-number statistics. With feedback, the fraction is larger because of the reaccretion of gas heated by supernovae, which has lower entropies and shorter cooling times than the gas heated by accretion shocks. We have compared the results of NIHAO to predictions of the GalICS 2.1 semianalytic model of galaxy formation. The shock-stability criterion implemented in GalICS 2.1 successfully reproduces the transition from cold- to hot-mode accretion.
