论文标题
在射手群矮人球形星系的球状簇中的潮汐大恒星候选者
Extra-tidal star candidates in globular clusters of the Sagittarius dwarf spheroidal galaxy
论文作者
论文摘要
与Sagittarius矮人球星系（SGR DSPH）相关的球状簇（GCS）在SGR DSPH和银河系的重力下都进化了。 The effects of these potentials are most pronounced in the extra-tidal regions as compared to the central regions of the GCs.We aim to study the extra-tidal regions of the GCs that are possibly associated with Sgr dSph, namely Arp 2, Terzan 8, NGC 5634, NGC 6284, Terzan 7, NGC 2419, NGC 4147, M 54 and Pal 12, using data从{\ it gaia}早期数据版本3中。我们根据其距离群集中心的角距离选择了潮汐外候选，在RA-DEC平面中的群集中心，适当的运动和单个潮汐恒星候选者的适当运动，以及它们在clusters colour-Magemagnitude clusor-ligermagniper-lighters clusters图中的位置。我们找到了九个研究的GCS的潮汐外候选者。对于其中的八个，相对于周围更遥远的场，群集附近候选潮汐恒星的表面密度显着过多。对于任何集群，未检测到超过5个潮汐半径以外的延长潮汐外特征。我们发布了使用GAIA星形和光度数据确定的最可能的潮汐外候选列表。我们的分析表明，与SGR DSPH相关的簇更有可能受SGR的重力影响，因为潮汐外恒星的分布与局部流相同的方向伸长。 NGC 4147是唯一的例外。我们在几个分析的群集中发现了一些高概率候选潮汐恒星。我们未能检测到周围的任何一致的大规模潮汐尾巴。
Globular clusters (GCs) associated with the Sagittarius dwarf spheroidal galaxy (Sgr dSph) have evolved under the gravitational potential of both Sgr dSph and the Milky Way. The effects of these potentials are most pronounced in the extra-tidal regions as compared to the central regions of the GCs.We aim to study the extra-tidal regions of the GCs that are possibly associated with Sgr dSph, namely Arp 2, Terzan 8, NGC 5634, NGC 6284, Terzan 7, NGC 2419, NGC 4147, M 54 and Pal 12, using data from the {\it Gaia} early data release 3. We selected the extra-tidal candidates based on their angular distances from the cluster centre in the RA-Dec plane, proper motions of the clusters and the individual extra-tidal star candidates, and their positions on the colour-magnitude diagrams of the clusters. We found extra-tidal candidates for the nine studied GCs. For eight of them, the surface density of candidate extra-tidal stars in the vicinity of the clusters is in significant excess with respect to more distant surrounding fields. No extended extra-tidal features beyond 5 tidal radii were detected for any of the clusters. We publish a list of the most probable extra-tidal candidates that we determined using Gaia astrometric and photometric data. Our analysis shows that the clusters that are associated with Sgr dSph are more likely affected by the gravitational potential of the Sgr, as the distribution of extra-tidal stars is elongated in the same direction as the local stream. NGC 4147 is the only exception. We found some high-probability candidate extra-tidal stars in several of the analysed clusters. We failed to detect any coherent large-scale tidal tail around them.
