分子碎裂
Molecular Shattering
AI总结：
本文通过辐射无黏流体动力学模拟研究偏离压力平衡的分子云碎裂，提出临界尺寸、声音穿越时间判据及旋转驱动的“splintering”机制。
摘要：
近期观测表明，星系的多相环星系介质（CGM）中可能普遍存在分子成分。然而，分子CGM的结构和运动学在理论上仍研究不足，在观测上也基本缺乏约束。近期研究表明，具有高效冷却能力的分子气体云能在热风加速中存活，这与原子云类似。但是，分子云在遭受外部激波或经历冷却时由压力驱动的碎裂过程仍未得到研究。我们对偏离压力平衡而受扰动的云进行了辐射、无黏流体动力学模拟，以探索冷却至分子温度过程中的流体动力学碎裂机制。我们发现，大于临界尺寸的分子云会碎裂成由微小液滴组成的雾，而该临界尺寸与原子情形显著不同。我们发现，冷云只有在声音穿越时间超过约8000 K处冷却时间的局部最大值时才会碎裂。此外，我们发现证据表明存在一种由旋转碎裂导致冷云“碎裂”成微小液滴“雾”的普遍机制——我们将这一过程命名为“splintering（劈裂）”。我们的结果对于在观测和宇宙学模拟中分辨CGM的分子相具有意义。
英文摘要：
Recent observations suggest galaxies may ubiquitously host a molecular component to their multiphase circumgalactic medium (CGM). However, the structure and kinematics of the molecular CGM remains understudied theoretically and largely unconstrained observationally. Recent work suggests molecular gas clouds with efficient cooling survive acceleration in hot winds similar to atomic clouds. Yet the pressure-driven fragmentation of molecular clouds when subjected to external shocks or undergoing cooling remains unstudied. We perform radiative, inviscid hydrodynamics simulations of clouds perturbed out of pressure equilibrium to explore the process of hydrodynamic fragmentation to molecular temperatures. We find molecular clouds larger than a critical size can shatter into a mist of tiny droplets, with the critical size deviating significantly from the atomic case. We find that cold clouds shatter only if the sound crossing time exceeds the local maximum of the cooling time ~8000 K. Moreover, we find evidence for a universal mechanism to 'shatter' cold clouds into a 'mist' of tiny droplets as a result of rotational fragmentation -- a process we dub 'splintering.' Our results have implications for resolving the molecular phase of the CGM in observations and cosmological simulations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
