论文标题
快速HI气体碰撞形成大型星团
Formation of Massive Star Clusters by Fast HI Gas Collision
论文作者
论文摘要
年轻的大型簇（YMC）是年轻恒星的致密聚集体，这对于星系进化至关重要，由于它们的紫外线，恒星风和超新星。 YMC的典型质量和半径分别为m〜10^4 m_sun和r〜1 pc，表明许多恒星位于一个小区域。 YMC前体云的形成可能很困难，因为在恒星反馈吹出云之前，应形成非常紧凑的巨大云。最近的观察性研究表明，YMC可以是由于快速HI气体碰撞而形成的，其速度约为100 km S^-1，这是星系 - 果胶相互作用的典型速度。在这项研究中，我们检查了快速HI气体碰撞是否使用三维磁性水力学模拟触发了YMC的形成，其中包括自我重力，辐射冷却/加热和化学的影响。我们证明，在快速HI气体碰撞引起的冲击压缩区域中形成了M> 10^4 m_sun和L〜4 PC的大量重力结合的气体团块，大量气体团块可以演变为YMC。我们的结果表明，YMC前体是由分子云的全球重力崩溃形成的，即使在低金属环境（例如麦哲伦云）中，也可以形成YMC。此外，当我们考虑HI云的快速碰撞时，可以创建非常庞大的YMC前体云，具有m> 10^5 m_sun，这可以解释大麦芽云中非常庞大的恒星群集R136系统的起源。
Young massive clusters (YMCs) are dense aggregates of young stars, which are essential to galaxy evolution, owing to their ultraviolet radiation, stellar winds, and supernovae. The typical mass and radius of YMCs are M~10^4 M_sun and R~1 pc, respectively, indicating that many stars are located in a small region. The formation of YMC precursor clouds may be difficult because a very compact massive cloud should be formed before stellar feedback blows off the cloud. Recent observational studies suggest that YMCs can be formed as a consequence of the fast HI gas collision with a velocity of ~100 km s^-1, which is the typical velocity of the galaxy-galaxy interaction. In this study, we examine whether the fast HI gas collision triggers YMC formation using three-dimensional magnetohydrodynamics simulations, which include the effects of self-gravity, radiative cooling/heating, and chemistry. We demonstrate that massive gravitationally bound gas clumps with M >10^4 M_sun and L~4 pc are formed in the shock compressed region induced by the fast HI gas collision, which massive gas clumps can evolve into YMCs. Our results show that the YMC precursors are formed by the global gravitational collapse of molecular clouds, and YMCs can be formed even in low-metal environments, such as the Magellanic Clouds. Additionally, the very massive YMC precursor cloud, with M >10^5 M_sun, can be created when we consider the fast collision of HI clouds, which may explain the origin of the very massive stellar cluster R136 system in the Large Magellanic Cloud.
