EROSE：一种用于搜寻已解析的本星系群卫星的算法。结合不同测光波段对LSST中银河系卫星可探测性的影响
EROSE: An algorithm searching for resolved Local Group satellites. The impact of combining different photometric bands on the detectability of Milky Way satellites in the LSST
中文总结 AI 辅助
本研究提出新型多波段搜寻算法EROSE，结合LSST的ugri测光波段搜寻银河系超暗矮卫星，发现u-g组合恢复率最高，可提升低质量端卫星的探测能力并约束暗物质模型。
中文摘要 AI 辅助
对银河系超暗矮卫星星系的系统搜寻通常将局部密度估计器与色-星等截断相结合，这类操作一般在二维空间中进行，极少扩展到更高维空间。这类研究通常依赖gri测光，忽略了较浅但对金属敏感的u波段。进入LSST时代，本研究探索不同ugri组合以确定哪种组合性能最佳。我们将36000个矮星系注入LSST数据挑战2（DC2）的模拟数据中，并尝试用EROSE（一种新型快速多波段搜寻算法，设计用于轻松应用于任何巡天和测光波段组合）恢复这些矮星系。我们发现，结合所有三个gri测光波段的多色-星等空间，平均而言略优于仅结合gr或ri的常用色-星等空间。使用结合u和g波段的色-星等空间可获得最高恢复率，平均恢复64.1⁺⁶.³₋₆.₀%的注入卫星。这种改进在最延展的系统中尤为明显，u波段提供的额外色信息提升了我们从污染的前景天体中分离贫金属成员星的能力。我们估计，LSST将发现约50个新的银河系矮星系，在其覆盖范围内使已知卫星数量翻倍以上。将LSST测光波段与基于空间的星/星系分离相结合可进一步改进这些结果，使我们能发现银河系卫星星系光度函数低质量端的卫星，并为暗物质模型提供有价值的约束。
英文摘要
Systematic searches for ultra-faint Milky Way satellite galaxies typically combine local density estimators with colour-magnitude cuts, which are usually performed in 2D and have rarely, if ever, been extended to higher-dimensional spaces. These studies generally rely on $gri$ photometry, overlooking the shallower but metal-sensitive $u$ band. Entering the era of LSST, our study explores different $ugri$ combinations to determine which provides the best performance. We injected 36,000 dwarf galaxies into the simulated data from the LSST Data Challenge 2 (DC2) and attempted to recover them using EROSE, a new fast multi-band search algorithm designed to be easily applied to any survey and combination of photometric bands. We find that a multi-colour-magnitude space combining all three $gri$ photometric bands slightly outperforms, on average, the more commonly used colour-magnitude spaces combining only $gr$ or $ri$. The highest recovery fraction is achieved using a colour-magnitude space combining the $u$ and $g$ bands, recovering, on average, $64.1^{+6.3}_{-6.0}\%$ of the injected satellites. This improvement is particularly evident for the most extended systems, for which the additional colour information provided by the $u$ band improves our ability to isolate metal-poor member stars from contaminating foreground populations. We estimate that the LSST will discover $\sim 50$ new Milky Way dwarf galaxies, more than doubling the currently known number of satellites within its footprint. Combining the LSST photometric bands with a space-based star/galaxy separation could further improve these results, enabling the discovery of satellites at the low-mass end of the Milky Way's satellite galaxy luminosity function and providing valuable constraints on dark matter models.
