LATED：基于Ly$\alpha$锚定的光度选择，从再电离末期到宇宙正午的候选无金属及极贫金属恒星形成
LATED: Ly$α$-anchored photometric selection of candidate metal-free and extremely metal-poor star formation from the end of reionisation to cosmic noon
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中文总结 AI 辅助
LATED利用Ly$\alpha$锚定的强线诊断光度方法，在红移1.92-6.60范围内高效筛选无金属及极贫金属恒星形成候选体，为光谱后续观测提供优先目标。
中文摘要 AI 辅助
宇宙学模拟允许第三星族（Pop III）恒星形成的低水平尾部持续到$z=2-6$。光谱确认成本高昂，因此需要一种高效的光度预选方法。我们提出LATED（极贫金属区域的莱曼阿尔法层析成像），该方法利用强线诊断，从Ly$\alpha$发射体母样本中选出无金属和极贫金属候选体。该方法需要三个波段和两个颜色，$x=m_{\rm OIII}-m_{{\rm H}\alpha}$和$y=m_{{\rm H}\alpha}-m_{\rm cont}$，分别追踪氧丰度和H$\alpha$等效宽度。要求滤光片同时包含[O III]+H$\beta$和H$\alpha$，并结合Ly$\alpha$母体选择，定义了跨越$z=1.92-6.60$的五个窗口（四个JWST/NIRCam，一个Roman/WFI）。判据$x\geq x_{\rm min}(z)$和$y\leq y_{\rm max}(z)$由前向模拟的Pop III模板轨迹在每个红移处的极值设定。普通富金属恒星形成和AGN模板落在选择区域之外，可能的污染物如小红点通过其多波段颜色被标记。为实证检验污染，我们将LATED应用于1126个JADES光谱星系，在四个NIRCam窗口中未选出任何源。我们发布一个Python包，可将相同的光度转换为R3=[O III]/H$\beta$的测量值或上限，以0.12 dex的小散射重现JADES光谱。应用于Abell 2744中85个档案MUSE Ly$\alpha$发射体，LATED恢复了已确认的极贫金属星系AMORE6，并在$z=3-5$处揭示了三个新候选体。仅凭光度无法确定无金属性质。LATED为光谱后续观测提供优先候选体，为晚期Pop III恒星形成的系统性普查提供了一条可扩展的途径。
英文摘要
Cosmological simulations allow a low-level tail of Population III (Pop III) star formation to persist to $z=2-6$. Spectroscopic confirmation is expensive, so an efficient photometric pre-selection is needed. We present LATED (Lyman-Alpha Tomography of Extremely Metal-poor Domains), which selects metal-free and extremely metal-poor candidates from a Ly$α$-emitter parent sample using strong-line diagnostics. The method requires three bands and two colours, $x=m_{\rm OIII}-m_{{\rm H}α}$ and $y=m_{{\rm H}α}-m_{\rm cont}$, which trace oxygen abundance and the H$α$ equivalent width, respectively. Requiring that the filters simultaneously contain [O III]+H$β$ and H$α$, together with a Ly$α$ parent selection, defines five windows spanning $z=1.92-6.60$ (four JWST/NIRCam, one Roman/WFI). The criteria, $x\geq x_{\rm min}(z)$ and $y\leq y_{\rm max}(z)$, are set by the per-redshift extrema of a forward-modelled Pop III template locus. Ordinary metal-enriched star-forming and AGN templates fall outside the selection region, and possible contaminants such as little red dots are flagged by their multi-band colours. To check contamination empirically, we apply LATED to 1126 JADES spectroscopic galaxies, and no source is selected in the four NIRCam windows. We release a Python package which converts the same photometry into R3=[O III]/H$β$ as a measurement or upper limit, reproducing JADES spectroscopy with small 0.12 dex scatter. Applied to 85 archival MUSE Ly$α$ emitters in Abell 2744, LATED recovers the confirmed extremely metal-poor galaxy AMORE6 and reveals three new candidates at $z=3-5$. Photometry alone cannot establish a metal-free nature. LATED delivers prioritised candidates for spectroscopic follow-up, providing a scalable route toward a systematic census of late-time Pop III star formation.
