AI 中文总结
本研究通过N体模拟结合星系模型，探讨了银河系疏散星团群的演化，发现GMC并合对不同质量星团的瓦解影响存在显著差异，且强烈GMC并合的星团潮汐尾取向随机。
AI 中文摘要
我们研究了太阳邻域内疏散星团的群分布，并模拟了过去1 Gyr中巨分子云（GMC）并合产生的影响。我们将星系模型与20692个质量范围在[50-24000] M☉的独特星团的N体模拟相结合，每个星团均进行两组模拟：一组考虑GMC的潮汐力，另一组不考虑。我们发现，初始星团质量函数在约9000 M☉处截断时，能最好地复现观测到的质量函数演化。对于年龄函数，观测结果显示年龄大于约1 Myr的星团数量呈下降趋势，而我们的模拟星团在约50 Myr后才出现下降。观测到的早期瓦解现象表明部分星团形成时处于超维里平衡状态，而我们的模拟星团则形成于维里平衡状态。低质量（<600 M☉）星团对GMC并合最为敏感，在最初约200 Myr内，GMC并合会加速其瓦解；约500 Myr后，无论是否经历GMC并合，这些星团都会被摧毁，因此GMC并合的影响不再显著。中等质量（600-6000 M☉）星团在年龄达1 Gyr的过程中，其存活率因GMC并合而显著降低。高质量（>6000 M☉）星团无论是否经历GMC并合，都能存活至1 Gyr且瓦解程度极小。我们还发现，在过去20 Myr内经历过强烈GMC并合的星团，其潮汐尾相对于银心应呈随机取向。
英文摘要
We investigate the population of open clusters in the Solar Neighbourhood and model the effect of encounters with giant molecular clouds (GMCs) over the last 1 Gyr. We combine a Galactic model with $N$-body simulations of 20692 unique clusters in the mass range $[50-24000]$ $\mathrm{M}_{\odot}$. Each cluster is simulated twice: with and without tidal forces from the GMCs. We find that an initial cluster mass function truncated at $\sim 9000$ $\mathrm{M}_{\odot}$ best reproduces the observed mass function evolution. For the age function, the observations show a decline in clusters for ages older than $\sim 1$ Myr, whereas our simulated clusters show a decline after $\sim 50$ Myr. The observed early disruption suggests that some clusters form supervirial, whereas our simulated clusters are created in virial equilibrium. Low-mass ($<600 \, \mathrm{M}_{\odot}$) clusters are most sensitive to GMC encounters, which accelerate their disruption in the first $\sim 200$ Myr. After $\sim 500$ Myr, the impact of GMCs becomes irrelevant since the clusters will have been destroyed regardless of whether they experience GMC encounters or not. The survival of intermediate-mass ($600-6000\, \mathrm{M}_{\odot}$) clusters is significantly reduced by GMCs at ages up to 1 Gyr. High-mass ($>6000 \, \mathrm{M}_{\odot}$) clusters survive to 1 Gyr with minimal disruption with or without GMCs. We find that clusters that have had strong GMC encounters within the last $20$ Myr should have tidal tails that are randomly orientated with respect to the Galactic centre.
