Recent advances from astronomical surveys have revealed spatial, chemical, and kinematical inhomogeneities in the inner region of the stellar halo of the Milky Way Galaxy. In particular, large spectroscopic surveys, combined with Gaia astrometric data, have provided powerful tools for analyzing the detailed abundances and accurate kinematics for individual stars. Despite these noteworthy efforts, however, spectroscopic samples are typically limited by the numbers of stars considered; their analysis and interpretation are also hampered by the complex selection functions that are often employed. Here we present a powerful alternative approach $-$ a synoptic view of the spatial, chemical, and kinematical distributions of stars in the Milky Way based on large photometric survey databases, enabled by a well-calibrated technique for obtaining individual stellar metal abundances from broad-band photometry. We combine metallicities with accurate proper motions from the Gaia mission along the Prime Meridian of the Galaxy, and find that various stellar components are clearly separated from each other in the metallicity versus rotation-velocity space. The observed metallicity distribution of the inner-halo stars deviates from the traditional single-peaked distribution, and exhibits complex substructures comprising varying contributions from individual stellar populations, sometimes with striking double peaks at low metallicities. The substructures revealed from our less-biased, comprehensive maps demonstrate the clear advantages of this approach, which can be built upon by future mixed-band and broad-band photometric surveys, and used as a blueprint for identifying the stars of greatest interest for upcoming spectroscopic studies.

中文翻译：

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银河系恒星群的蓝图：大型光度测量和天体测量测量的力量

天文调查的最新进展揭示了银河系恒星晕内部区域的空间、化学和运动不均匀性。特别是大型光谱调查，结合盖亚天体测量数据，为分析单个恒星的详细丰度和精确运动学提供了强大的工具。然而，尽管做出了这些值得注意的努力，光谱样本通常受到所考虑的恒星数量的限制。他们的分析和解释也受到经常使用的复杂选择功能的阻碍。在这里，我们提出了一种强大的替代方法 $-$ 基于大型光度测量数据库的银河系中恒星的空间、化学和运动学分布的概要视图，通过校准良好的技术实现从宽带光度测量中获得单个恒星金属丰度。我们将金属丰度与盖亚任务沿着银河系本初子午线的精确自行结合起来，发现各种恒星成分在金属丰度与旋转速度空间中彼此明显分离。观测到的内晕星的金属丰度分布与传统的单峰分布不同，并表现出复杂的子结构，包括来自各个星族的不同贡献，有时在低金属丰度时具有惊人的双峰。从我们的偏差较小的综合地图中揭示的子结构证明了这种方法的明显优势，未来的混合波段和宽带光度测量可以建立这种优势，