牧夫座III（Boo3）的扰动特征：银晕中缺失的一环？
Characterizing the disruption of Böotes III: a missing link in the Galactic halo?
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中文总结 AI 辅助
研究Boo3与Styx恒星流的关联，结合多波段数据搜索Boo3的潮汐碎片，未发现二者直接关联的证据，凸显需后续光谱观测厘清二者性质。
中文摘要 AI 辅助
长期以来，牧夫座III（Boo3）矮星系被认为是冥河（Styx）恒星流的前身，该恒星流同时在同一天区被发现，长度约50°。Boo3的弥散形态、大速度弥散、小近心点以及大半径处候选恒星过量，表明它正在经历活跃的潮汐扰动，因此它与Styx存在关联是合理的，但这些结构之间的明确联系尚未得到清晰证实。本文通过结合盖亚（Gaia）选取的成员星、加拿大-法国-夏威夷望远镜（CFHT）/MegaCam的新CaHK窄带成像，以及水平分支蓝星和红巨星分支星的恒星示踪星表，重新研究Boo3与Styx的关联，还对SDSS DR17和DELVE DR2应用匹配滤波技术，广泛搜索假定的恒星流。尽管进行了广泛搜索，未发现Boo3与Styx直接关联的观测证据；结果表明，要么Boo3的延展子结构过于弥散，现有数据无法探测，要么其特定轨道可能抹去了相干的潮汐信号。因此，Boo3仍是一个神秘系统，凸显了后续光谱观测对于正确厘清这个暗弱银河系卫星星系与附近恒星流之间性质的必要性。
英文摘要
The Böotes III (Boo3) dwarf galaxy has long been suspected of being the progenitor of Styx, a ~50°-long stellar stream that was simultaneously discovered in the same region of sky. Boo3's diffuse morphology, large velocity dispersion, small pericenter, and excess of candidate stars at large radii suggest it is undergoing active tidal disruption. A link to Styx is therefore logical; however, a clear connection between these structures has not yet been clearly demonstrated. Here, we re-examine the Boo3-Styx association by searching for Boo3's tidal debris using a combination of Gaia-selected members, new CaHK narrow-band imaging with CFHT/MegaCam, and stellar tracer catalogues of blue horizontal branch and red giant branch stars. We also conduct a broad search for a putative stream using matched filter techniques applied to SDSS DR17 and DELVE DR2. Despite our extensive search, we find no observational evidence directly linking Boo3 to Styx. Furthermore, our results suggest that either Boo3's extended substructure is too diffuse to be detected with current data, or that its particular orbit may have erased a coherent tidal signature. Boo3 thus remains an enigmatic system, and exemplifies the need for spectroscopic follow-up to properly disentangle the nature between this faint Milky Way satellite and nearby stream.
