Title: Statistical Analysis of the Probability of Interaction of Globular Clusters with Each Other and with the Galactic Center on the Cosmological Time Scale According to Gaia DR2 Data Show Chinese title

Title: 根据盖亚DR2数据的球状星团在宇宙时间尺度上相互之间以及与银河系中心相互作用的概率统计分析

Abstract: This study is aimed at investigating the dynamic evolution of the orbits of stellar globular clusters (GCs). To integrate the orbits backward in time, the authors use models of the time-varying potentials derived from cosmological simulations, which are closest to the potential of the Galaxy. This allows for estimating the probability of close passages (collisions) of GCs with respect to each other and the Galactic center (GalC) in the Galaxy undergoing dynamic changes in the past. To reproduce the dynamics of the Galaxy in time, five potentials selected from the IllustrisTNG-100 large-scale cosmological database, which are similar in their characteristics to the current physical parameters of the Milky Way, are used. With these time-varying potentials, we have reproduced the orbital trajectories of 143 GCs 10 Gyr back in time using our original phi-GPU N-body code. Each GC was treated as a single physical particle with the assigned position and velocity of the cluster center from the Gaia DR2 observations. For each of the potentials, 1000 initial conditions were generated with randomized initial velocities of GCs within the errors of the observational data. In this study, we consider close passages to be passages with a relative distance of less than 100 pc and a relative speed of less than 250 km/s. To select clusters that pass at close distances from the GalC, the following criterion is applied based only on the relative distance: it must be less than 100 pc. Applying the above criteria, the authors obtained statistically significant rates of close passages of GCs with respect to each other and to the GalC. It has been determined that GCs during their evolution have approximately 10 intersecting trajectories with each other on the average and approximately 3 to 4 close passages near the GalC in 1 Gyr at a distance of 50 pc for each of the chosen potentials. Show Chinese abstract

Abstract: 本研究旨在探讨恒星球状星团（GCs）轨道的动态演化。 为了将轨道向过去时间整合，作者使用了从宇宙学模拟中得出的随时间变化的势模型，这些模型最接近银河系的势。 这使得能够在银河系在过去经历动态变化的情况下，估计星团之间以及与银河系中心（GalC）之间的近距离通过（碰撞）概率。 为了在时间上再现银河系的动力学，使用了从IllustrisTNG-100大规模宇宙学数据库中选择的五个势，这些势在特性上与当前银河系的物理参数相似。 利用这些随时间变化的势，我们使用我们原创的phi-GPU N体代码，将143个GC的轨道轨迹重现了10 Gyr以前。 每个GC被当作一个单一的物理粒子处理，其位置和速度由Gaia DR2观测数据中的星团中心指定。 对于每个势，生成了1000组初始条件，GC的初始速度在观测数据的误差范围内随机化。 在本研究中，我们认为近距离通过是指相对距离小于100 pc且相对速度小于250 km/s的通过。 为了选择距离GalC较近的星团，仅基于相对距离应用以下标准：必须小于100 pc。 应用上述标准后，作者获得了星团之间以及与GalC之间近距离通过的统计显著率。 已经确定，在演化过程中，GCs平均彼此有大约10条交叉轨迹，并且在所选势的每个情况下，在50 pc的距离内每1 Gyr大约有3到4次靠近GalC的近距离通过。