标题： 分级流体动力学模拟中的盘形成：解决角动量灾难的方法 显示英文标题

标题： Disk Formation In Hierarchical Hydrodynamical Simulations: A Way Out Of The Angular Momentum Catastrophe

摘要： 我们报告在分层聚类场景中的两个宇宙学流体动力学模拟中盘状结构的形成结果，这两个模拟具有相同的初始条件。 在第一个模拟中，一种简单且通用的恒星形成实现使得类似星系的天体形成，这些天体具有恒星核球和扩展且充满的盘。 盘中的气体既来自在合并过程中存活下来的粒子，这些粒子部分保留了它们的角动量，也来自合并过程结束后通过吸积补充的新气体，此时整体比角动量保持守恒。 恒星核球由失去大部分角动量的气体形成。 在第二个模拟中，没有包含恒星形成。 在这种情况下，天体由一个过度填充的中心气体浓度和一个扩展且填充不足的盘组成。 中心浓度由在剧烈事件中损失重要角动量的粒子形成，它通常包含超过70%的天体重子质量。 外部盘通过晚期气体吸积形成，这些气体大致保持其比角动量。 这两个模拟之间的差异可能是由于第一个模拟中形成的类似恒星核球的核心的稳定作用，这减少了由合并和相互作用引发的气体流入。 显示英文摘要

摘要： We report results on the formation of disk-like structures in two cosmological hydrodynamical simulations in a hierarchical clustering scenario, sharing the same initial conditions. In the first one, a simple and generic implementation of star formation has allowed galaxy-like objects with stellar bulges and extended, populated disks to form. Gas in the disk comes from both, particles that survive mergers keeping in part their angular momentum content, and new gas supply by infall, once the merger process is over, with global specific angular momentum conservation. The stellar bulge forms from gas that has lost most of its angular momentum. In the second simulation, no star formation has been included. In this case, objects consist of an overpopulated central gas concentration, and an extended, underpopulated disk. The central concentration forms from particles that suffer an important angular momentum loss in violent events, and it often contains more than 70% of the object's baryonic mass. The external disk forms by late infall of gas, that roughly conserves its specific angular momentum. The difference between these two simulations is likely to be due to the stabilizing character of the stellar bulge-like cores that form in the first simulation, which diminishes the inflow of gas triggered by mergers and interactions.