论文标题
盖亚在球状簇结构上的眼睛：潮汐尾巴
The eye of Gaia on globular clusters structure: tidal tails
论文作者
论文摘要
我使用GAIA任务的第二个数据释放提供的光度和天文信息分析了在18个银河球状簇周围的大面积上的成员恒星的预计密度分布。已经采用了一种5D混合物建模技术来最佳地隔离簇恒星种群的信号，从银河场的污染中，利用了其在颜色，大小，差异和适当运动形成的空间中的不同分布。在7个簇中，我检测到高于背景密度> 3的Sigma水平的准过过度，延伸到群集潮汐半径之外，这与由于潮汐相互作用与银河系潜力的潮汐相互作用而导致的失真。在这些簇中的五个（NGC288，NGC2298，NGC5139，NGC6341和NGC7099）中，壮观的潮汐尾巴延伸至来自中心5度的分析视野的边界。在距离群集中心的距离很远的地方，检测到的过度的方向似乎与群集轨道路径有系统地对齐，这与N体模拟的预测一致。这些簇的潮汐尾巴中包含的恒星的比例也用于确定其当今破坏率的首次观察估计。
I analyse the projected density distribution of member stars over a wide area surrounding 18 Galactic globular clusters using the photometric and astrometric information provided by the second data release of the Gaia mission. A 5D mixture modelling technique has been employed to optimally isolate the signal of the cluster stellar population from the contamination of the Galactic field, taking advantage of its different distribution in the space formed by colours, magnitudes, parallaxes and proper motions. In 7 clusters I detect collimated overdensities at a >3 sigma level above the background density extending well beyond the cluster tidal radius, consistent with the distortion expected as a result of the tidal interaction with the Milky Way potential. In five of these clusters (NGC288, NGC2298, NGC5139, NGC6341 and NGC7099) spectacular tidal tails extend up to the border of the analysed field of view at 5 degrees from the centre. At large distances from the cluster centre, the orientation of the detected overdensities appears to be systematically aligned with the cluster orbital path, in agreement with the predictions of N-body simulations. The fraction of stars contained in the tidal tails of these clusters is also used to determine the first observational estimate of their present-day destruction rates.
