Bar-driven leading spiral arms in a counter-rotating dark matter halo
Bar-driven leading spiral arms in a counter-rotating dark matter halo
复制标题
反向旋转暗物质晕中棒驱动的前旋臂
DOI：
10.1093/mnras/stab2904
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发表时间：
2021
影响因子：
4.8
通讯作者：
Madigan, Ann-Marie
中科院分区：
文献类型：
--
作者：
Lieb, Emma;Collier, Angela;Madigan, Ann-Marie
绝大多数星系的旋臂都与星系的自转有关，尽管已经观察到一小部分领先的旋臂。这些领先螺旋的形成还没有被很好地理解。在这里，我们使用无碰撞N体模拟表明，在逆行暗物质晕中的条状盘状星系可以产生长寿命(∼3)领先旋臂。由于圆盘与光晕的强共振耦合，棒的速度迅速减慢，螺旋扰动被强迫在棒的前面。我们预测，如果观测到这样一个系统，它还将拥有一个垂直于恒星棒的暗物质尾迹。更广泛地说，我们提出，任何快速减速恒星棒的机制都将允许领先的旋臂蓬勃发展。
An overwhelming majority of galactic spiral arms trail with respect to the rotation of the galaxy, though a small sample of leading spiral arms has been observed. The formation of these leading spirals is not well understood. Here we show, using collisionlessN-body simulations, that a barred disc galaxy in a retrograde dark matter halo can produce long-lived (∼3 Gyr) leading spiral arms. Due to the strong resonant coupling of the disc to the halo, the bar slows rapidly and spiral perturbations are forced ahead of the bar. We predict that such a system, if observed, will also host a dark matter wake oriented perpendicular to the stellar bar. More generally, we propose that any mechanism that rapidly decelerates the stellar bar will allow leading spiral arms to flourish.