论文标题
Pegasus-Pisces Arch Arch中间速度云的长尾巴
The Long Tails of the Pegasus-Pisces Arch Intermediate Velocity Cloud
论文作者
论文摘要
我们提出了Pegasus-Pisces（PP Arch）的流体动力模拟，这是我们银河系中的中间速度云。 PP弓，也称为IVC 86-36，在中间和高速云中是独一无二的，因为其双尾巴异常长和狭窄。其-50 km/s的视线速度将其视为中间速度云，但尾巴的方向表明云的总三维速度至少为约100 km/s。这种速度在雷诺的层和较厚的磁盘中是超音速的。我们模拟了云，因为它与中平面相对于中平面以倾斜角度通过银河厚和薄磁盘进行了模拟。我们的模拟云长长双尾巴，并合理地再现了PP拱门头部的H I 21〜cm强度和速度。弓震可保护每个模拟的云免受过多的剪切，并降低其雷诺数。这些因素可能会类似地保护PP拱门，并使其异常长的尾巴生存。模拟预测云与近乎银河中平面的浓密气体相撞时的未来流体动力行为。看来，PP Arch的命运是变形，消散并与银河盘合并。
We present hydrodynamic simulations of the Pegasus-Pisces (PP Arch), an intermediate velocity cloud in our Galaxy. The PP Arch, also known as IVC 86-36, is unique among intermediate and high velocity clouds, because its twin tails are unusually long and narrow. Its -50 km/s line-of-sight velocity qualifies it as an intermediate velocity cloud, but the tails' orientations indicate that the cloud's total three-dimensional speed is at least ~100 km/s. This speed is supersonic in the Reynold's Layer and thick disk. We simulated the cloud as it travels supersonically through the Galactic thick and thin disks at an oblique angle relative to the midplane. Our simulated clouds grow long double tails and reasonably reproduce the H I 21~cm intensity and velocity of the head of the PP Arch. A bow shock protects each simulated cloud from excessive shear and lowers its Reynolds number. These factors may similarly protect the PP Arch and enable the survival of its unusually long tails. The simulations predict the future hydrodynamic behavior of the cloud when it collides with denser gas nearer to the Galactic midplane. It appears that the PP Arch's fate is to deform, dissipate, and merge with the Galactic disk.
