由一颗下落的卫星引起的气体导引
Gas Shepherding by an Infalling Satellite
摘要：
我计算行动的卫星，通过动力摩擦，共面气体磁盘有限的径向范围。由下落的卫星引起的盘潮使卫星和盘耦合。作用在卫星上的动力摩擦力使耦合的卫星-圆盘系统的半径缩小。因此，气体被“引导”到更小的半径。此外，气体引导在盘边缘产生大的表面密度增强。如果盘的边缘变得重力不稳定并碎裂，它可能会增强恒星的形成。另一方面，如果卫星的质量和密度足够大，气体可能会从$\sim 100$ pc转移到10到10秒差距内，然后完全分裂成恒星。我认为，气体牧羊可能会推动活跃星系和中央星暴的燃料，我比较这种情况下竞争的情况。我认为，足够大和密集的超级星团（充当牧羊人卫星）可以将气体盘引导到10到几十秒差距。在十到几十秒差距内，另一种机制可能起作用，即，云-云碰撞或边缘（重力）稳定的磁盘，驱动气体$\lesssim 1$ pc，在那里它可以粘性地增生，供给中央引擎。
英文摘要：
I calculate the action of a satellite, infalling through dynamical friction, on a coplanar gaseous disk of finite radial extent. The disk tides, raised by the infalling satellite, couple the satellite and disk. Dynamical friction acting on the satellite then shrinks the radius of the coupled satellite-disk system. Thus, the gas is ``shepherded'' to smaller radii. In addition, gas shepherding produces a large surface density enhancement at the disk edge. If the disk edge then becomes gravitationally unstable and fragments, it may give rise to enhanced star formation. On the other hand, if the satellite is sufficiently massive and dense, the gas may be transported from $\sim 100$ pc to inside of a 10 to 10s of parsecs before completely fragmenting into stars. I argue that gas shepherding may drive the fueling of active galaxies and central starbursts and I compare this scenario to competing scenarios. I argue that sufficiently large and dense super star clusters (acting as the shepherding satellites) can shepherd a gas disk down to ten to tens of parsecs. Inside of ten to tens of parsecs, another mechanism may operate, i.e., cloud-cloud collisions or a marginally (gravitationally) stable disk, that drives the gas $\lesssim 1$ pc, where it can be viscously accreted, feeding a central engine.
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。
