Spectroscopic signatures of extratidal stars around the globular clusters NGC 6656 (M 22), NGC 3201, and NGC 1851 from RAVE
Spectroscopic signatures of extratidal stars around the globular clusters NGC 6656 (M 22), NGC 3201, and NGC 1851 from RAVE
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DOI：
10.1051/0004-6361/201424113
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发表时间：
2014-08
影响因子：
6.5
通讯作者：
A. Kunder;G. Bono;T. Piffl;M. Steinmetz;E. Grebel;B. Anguiano;K. Freeman;G. Kordopatis;T. Zwitter;R. Scholz;B. Gibson;J. Bland-Hawthorn;G. Seabroke;C. Boeche;A. Siebert;R. Wyse;O. Bienaymé;J. Navarro;A. Siviero;I. Minchev;Q. Parker;W. Reid;G. Gilmore;U. Munari;A. Helmi
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文献类型：
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作者：
A. Kunder;G. Bono;T. Piffl;M. Steinmetz;E. Grebel;B. Anguiano;K. Freeman;G. Kordopatis;T. Zwitter;R. Scholz;B. Gibson;J. Bland-Hawthorn;G. Seabroke;C. Boeche;A. Siebert;R. Wyse;O. Bienaymé;J. Navarro;A. Siviero;I. Minchev;Q. Parker;W. Reid;G. Gilmore;U. Munari;A. Helmi
上下文。对球状星团的恒星群研究表明，银河系中最亮的星团实际上可能是矮小球状星系的残核。如果现在的银河系球状星团是在更大的恒星系统内形成的，它们很可能被由恒星组成的外晕和/或尾巴所包围，这些恒星是从它们的母系统中被潮汐剥离的。目标。因此，球状星团周围的恒星环境是寻找古老矮小星系残骸的最佳地点之一。这里试图寻找超新星丰富的球状星团M22和NGC1851以及运动学上独特的星团NGC3201周围的潮汐碎片。方法：研究方法。来自径向速度实验(RAVE)的恒星参数被用来识别具有与M22、NGC1851和NGC3201恒星丰度模式和性质一致的RAVE金属度、径向速度和元素丰度的恒星。结果。据报道，发现了可能与M22和NGC1851有关的狂暴恒星，其中一些恒星距离这些星团的核心有10度的投影距离。许多与NGC3201有关的狂暴恒星表明，要么是这个星系团的潮汐半径被低估了，要么是一些未绑定的恒星从该星团半径的边缘延伸了几个弧分。没有发现其他与NGC3201有关的天外恒星。狂欢星的明亮级别使它们很容易成为高分辨率后续观测的目标，最终允许进一步的化学标记将星团潮汐半径以外的恒星固化(或排除)为潮汐碎片。在NGC1851和NGC3201周围区域的径向速度直方图中，可以看到在230公里处的恒星峰值S一号，这与来自！半人马座。
Context. Stellar population studies of globular clusters have suggested that the brightest clusters in the Galaxy might actually be the remnant nuclei of dwarf spheroidal galaxies. If the present Galactic globular clusters formed within larger stellar systems, they are likely to be surrounded by extratidal halos and/or tails made up of stars that were tidally stripped from their parent systems. Aims. The stellar surroundings around globular clusters are therefore one of the best places to look for the remnants of an ancient dwarf galaxy. Here an attempt is made to search for tidal debris around the supernovae enriched globular clusters M 22 and NGC 1851, as well as the kinematically unique cluster NGC 3201. Methods. The stellar parameters from the RAdial Velocity Experiment (RAVE) are used to identify stars with the RAVE metallicities, radial velocities, and elemental abundances that are consistent with the abundance patterns and properties of the stars in M 22, NGC 1851, and NGC 3201. Results. Discovery of RAVE stars that may be associated with M 22 and NGC 1851 are reported, some of which are at projected distances 10 degrees away from the core of these clusters. Numerous RAVE stars associated with NGC 3201 suggest that either the tidal radius of this cluster is underestimated or that there are some unbound stars extending a few arc minutes from the edge of the cluster’s radius. No other extratidal stars associated with NGC 3201 could be identified. The bright magnitudes of the RAVE stars make them easy targets for high-resolution follow-up observations, eventually allowing further chemical tagging to solidify (or exclude) stars outside the tidal radius of the cluster as tidal debris. In both our radial velocity histograms of the regions surrounding NGC 1851 and NGC 3201, a peak of stars at 230 km s 1 is seen, consistent with extended tidal debris from ! Centauri.