标题： 星系模型中由于盘加热导致的棒抑制数值研究 显示英文标题

标题： Numerical Study of Bar Suppression in Galaxy Models Due to Disc Heating

摘要： 棒状结构的形成、演化和破坏过程在星系动力学中仍然是一个有争议的话题。 数值模拟表明，这些现象强烈依赖于物理和数值参数。 在本研究中，我们通过不同粒子分辨率的$N$-体模拟，研究软化参数$\epsilon$和盘质量分数$m_{\mathrm{d}}$对孤立盘-晕模型中棒状结构形成和演化的影响。 先前的研究表明，棒的强度取决于$m_{\mathrm{d}}$作为$\propto m_{\mathrm{d}}^{-1}$，这被视为棒形成的一种延迟。 然而，畸变参数$\eta$，它通过时间测量棒的动量，显示$m_{\mathrm{d}}$的增加并不总是导致棒形成的延迟。 这表明$\epsilon$相互作用以增强或削弱条状结构。 此外，在软化值较小的模型中，数值加热占主导地位，在盘的中心产生高度加速的粒子，无论$m_{\mathrm{d}}$或分辨率如何。 这些增强的粒子加速在$\epsilon \leq 5\,$pc 范围内产生混沌轨道，导致由于中心的碰撞动力学而抑制条状结构。 在我们的高分辨率模型（$N \approx 10^{7}$）中，小的软化值无法再现条状不稳定性。 盘质量的作用如下：对于中等的$\epsilon$（$\geq 10\,$pc），增加$m_{\mathrm{d}}$会减少加速度曲线中的漂移量，而不会影响条状结构的行为。 具有较低$m_{\mathrm{d}}$值且伴随较小的软化值的模型，会产生过多的高加速粒子，从而将不必要的效应引入原本可靠的模拟中。 最后，我们表明，盘的垂直加速度分布的变化是数值加热的可靠指示器，这种数值加热是由$\epsilon$和棒引起的。 显示英文摘要

摘要： The process of bar formation, evolution and destruction is still a controversial topic regarding galaxy dynamics. Numerical simulations show that these phenomena strongly depend on physical and numerical parameters. In this work, we study the combined influence of the softening parameter, $\epsilon$ and disc mass fraction, $m_{\mathrm{d}}$ on the formation and evolution of bars in isolated disc-halo models via $N$-body simulations with different particle resolutions. Previous studies indicate that the bar strength depends on $m_{\mathrm{d}}$ as $\propto m_{\mathrm{d}}^{-1}$, which is seen as a delay in bar formation. However, the distorsion parameter, $\eta$, which measures the bar's momentum through time, shows that an increase in $m_{\mathrm{d}}$ does not always induce a delay in bar formation. This suggests that $\epsilon$ interact to either enhance or weaken the bar. Moreover, numerical heating dominates in models with small softening values, creating highly accelerated particles at the centre of discs, regardless of $m_{\mathrm{d}}$ or resolution. These enhanced particle accelerations produce chaotic orbits for $\epsilon \leq 5\,$pc, resulting in bar suppression due to collisional dynamics in the centre. In our high resolution models ($N \approx 10^{7}$), small softening values are incapable of reproducing the bar instability. The role of disc mass is as follows: increasing $m_{\mathrm{d}}$ for moderate $\epsilon$ ($\geq 10\,$pc) reduces the amount of drift in the acceleration profile, without affecting the bar's behaviour. Models with lower $m_{\mathrm{d}}$ values coupled with small softening values, have an excess of highly accelerated particles, introducing unwanted effects into otherwise reliable simulations. Finally, we show that the evolution of the disc's vertical acceleration profile is a reliable indicator of numerical heating introduced by $\epsilon$ and the bar.