论文标题
在旋转曲线的剪切最小值处形成禁止星系的核环吗？
Do nuclear rings in barred galaxies form at the shear minimum of the rotation curve?
论文作者
论文摘要
最近有人提出（i）在旋转曲线的剪切参数达到最小值的半径上，禁止星系（包括我们自己的银河系）形式的核环； （ii）Montenegro等人的声学不稳定。负责驱动禁止星系中央区域的湍流和角动量传输。在这里，我们通过在对数中进行简单的流体动力学模拟来测试这些建议。由于该电势的旋转曲线是不含比例的，因此剪切最小理论预测不应形成环。我们发现，与该预测相反，在模拟中确实形成了一个环，形态与实际禁止星系中的核环相一致。这证明，剪切最小的存在不是形成环的必要条件。我们还发现，预计会在声学上不稳定并最终传播到无穷大的扰动，因此系统实际上是稳定的。我们得出的结论是，（i）剪切最低理论是在禁止星系中形成核环的一种不可能的机制； （ii）声学不稳定是一个虚假的结果，至少对于没有自我重力的情况，可能无法驱动星际介质的湍流。动荡粘度的作用的问题仍然开放。
It has been recently suggested that (i) nuclear rings in barred galaxies (including our own Milky Way) form at the radius where the shear parameter of the rotation curve reaches a minimum; (ii) the acoustic instability of Montenegro et al. is responsible for driving the turbulence and angular momentum transport in the central regions of barred galaxies. Here we test these suggestions by running simple hydrodynamical simulations in a logarithmic barred potential. Since the rotation curve of this potential is scale-free, the shear minimum theory predicts that no ring should form. We find that in contrast to this prediction, a ring does form in the simulation, with morphology consistent with that of nuclear rings in real barred galaxies. This proves that the presence of a shear-minimum is not a necessary condition for the formation of a ring. We also find that perturbations that are predicted to be acoustically unstable wind up and eventually propagate off to infinity, so that the system is actually stable. We conclude that (i) the shear-minimum theory is an unlikely mechanism for the formation of nuclear rings in barred galaxies; (ii) the acoustic instability is a spurious result and may not be able to drive turbulence in the interstellar medium, at least for the case without self-gravity. The question of the role of turbulent viscosity remains open.
