论文标题
博特斯的幽灵：最不发光的矮人银河系
A Ghost in Boötes: The Least Luminous Disrupted Dwarf Galaxy
论文作者
论文摘要
我们报告了Spectre的发现，Spectre是H3光谱调查揭示的一个破坏的超级矮星系。我们通过一对距离为12.5 kpc的一对共同的金属贫困恒星检测到了这种结构，并通过GAIA天文学和后续光谱进一步对其进行了表征。幽灵是$ 25^\ circ \ times 1^\ circ $ circ $ circ $ of Cress of stream of stream of Stars完全看不见，直到使用严格的运动学切割来删除银河前景为止。光谱成员建议恒星年龄$τ\ gtrsim 12 $ gyr和平均金属性$ \ langle \ langle \ text {[[fe/h]} \ rangle = -1.84 _ { - 0.18} 0.37 _ { - 0.13}^{+0.21} $。因此，我们认为幽灵是一个古老的矮人银河系中断的残留物。使用集成的光度$ m _ {\ text {v}} \大约-2.6 $，Specter是迄今为止最不发光的矮人星系流。我们估计，数十种类似的流潜伏在当前搜索技术的检测阈值以下，并得出结论，光谱调查提供了一种新颖的手段来识别极低的表面亮度结构。
We report the discovery of Specter, a disrupted ultrafaint dwarf galaxy revealed by the H3 Spectroscopic Survey. We detected this structure via a pair of comoving metal-poor stars at a distance of 12.5 kpc, and further characterized it with Gaia astrometry and follow-up spectroscopy. Specter is a $25^\circ \times 1^\circ$ stream of stars that is entirely invisible until strict kinematic cuts are applied to remove the Galactic foreground. The spectroscopic members suggest a stellar age $τ\gtrsim 12$ Gyr and a mean metallicity $\langle\text{[Fe/H]}\rangle = -1.84_{-0.18}^{+0.16}$, with a significant intrinsic metallicity dispersion $σ_{ \text{[Fe/H]}} = 0.37_{-0.13}^{+0.21}$. We therefore argue that Specter is the disrupted remnant of an ancient dwarf galaxy. With an integrated luminosity $M_{\text{V}} \approx -2.6$, Specter is by far the least-luminous dwarf galaxy stream known. We estimate that dozens of similar streams are lurking below the detection threshold of current search techniques, and conclude that spectroscopic surveys offer a novel means to identify extremely low surface brightness structures.
