论文标题
球状簇NGC 3201产生的潮汐流
The tidal stream generated by the globular cluster NGC 3201
论文作者
论文摘要
我们使用Gaia DR2数据检测到由球状簇NGC 3201生成的潮流，该潮流在天空上延伸了约140度，并使用了先前提出的最大似然方法来研究M68潮汐流。大多数检测到的溪流是尾流，它在南部的银河半球延伸，并在距太阳3.2 kpc的近距离距离之内，因此使溪流非常有利于发现相对明亮的成员恒星，而领先的臂离我们更远，磁盘前景更远，很难与更难分开。该集群刚刚越过银河盘，现在位于北部银河半球，被灰尘遮盖了，最接近簇的尾巴的一部分在飞机后面被高度掩盖。我们获得了流的最佳拟合模型，该模型与测得的运动，径向速度和距离NGC 3201的距离一致，并与Ibata等人的先前检测到的Gjöll流相同。我们仅使用其GAIA运动学数据来识别约200颗恒星，其可能性最高。这些恒星中的大多数（170）在光度法上与NGC 3201的成员相一致，当它们与簇H-R图进行了比较时，仅应用银河系校正了粉尘吸收和红色一次。根据模拟数据集，其余的恒星与随机前景对象一致。我们列出了这170个可能的流构件恒星，这将引起人们的浓厚兴趣，以对银河系的重力进行建模并进行频谱跟踪以获得准确的径向速度。
We detect a tidal stream generated by the globular cluster NGC 3201 extending over ~140 degrees on the sky, using the Gaia DR2 data, with the maximum likelihood method we presented previously to study the M68 tidal stream. Most of the detected stream is the trailing one, which stretches in the southern Galactic hemisphere and passes within a close distance of 3.2 kpc from the Sun, therefore making the stream highly favorable for discovering relatively bright member stars, while the leading arm is further from us and behind a disk foreground that is harder to separate from. The cluster has just crossed the Galactic disk and is now in the northern Galactic hemisphere, moderately obscured by dust, and the part of the trailing tail closest to the cluster is highly obscured behind the plane. We obtain a best-fit model of the stream which is consistent with the measured proper motion, radial velocity and distance to NGC 3201, and show it to be the same as the previously detected Gjöll stream by Ibata et al. We identify ~200 stars with the highest likelihood of being stream members using only their Gaia kinematic data. Most of these stars (170) are photometrically consistent with being members of NGC 3201 when they are compared to the cluster H-R diagram, only once a correction for dust absorption and reddening by the Galaxy is applied. The remaining stars are consistent with being random foreground objects according to simulated data sets. We list these 170 highly likely stream member stars, which will be of strong interest to model the gravitational potential of the Milky Way and to be followed up spectroscopically for accurate radial velocities.
