播种于宇宙黎明：在JWST JADES He II选发射线星系中搜寻Pop III信号
Sown at Cosmic Dawn: Searching for Pop III Signatures in JWST JADES He II Selected Line Emitters
- University of Manchester（曼彻斯特大学）
- University of Oxford（牛津大学）
- Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究在JWST JADES的84个强He II发射星系中搜寻Pop III恒星信号，未发现纯Pop III星系，但Blueberry和The Carrot为混合Pop III-Pop II候选体，表明Pop III信号可能局域化，需用分辨SED拟合识别。
AI中文摘要：
第三星族（Pop III）恒星，即第一代无金属恒星，至今仍未被探测到，部分原因是完全原始（pristine）的星系仅存在于一个短暂的阶段。我们转而瞄准寿命更长的自污染（self-polluted）和混合Pop III-Pop II阶段，在此类星系中，幸存的金属-free Pop III恒星与富含金属的气体及新形成的Pop II恒星共存，从而在产生可探测的紫外金属线的同时，产生强的He II发射。我们在JWST/JADES GOODS-South和GOODS-North天区中，结合紫外发射线诊断、气相金属丰度、活动星系核（AGN）筛查以及空间分辨的SED拟合，在z=3-7的84个强He II发射星系中搜寻这一特征。我们未发现任何原始Pop III星系的证据。相反，Blueberry（ID 13176，z=5.94）是我们最强的混合Pop III-Pop II系统候选体，也是唯一在所有诊断性紫外线上均有可靠探测的源。其分辨的恒星族极其年轻、蓝且消光较弱，具有高的恒星形成率，与近期强烈的恒星形成活动一致。尽管仅凭这些性质无法将其与化学增丰的星暴星系区分开来，但其可靠的紫外金属线比为我们样本中在增丰宿主内存在幸存Pop III贡献提供了最强证据。The Carrot（ID 13577，z=5.57）进一步展示了分辨分析的能力，揭示出其中心区域比整个星系显著更蓝、更年轻。综合来看，这些结果表明Pop III信号可能在空间上局域化，并在积分测量中被稀释，凸显了分辨SED拟合作为识别宇宙第一批恒星可能幸存环境工具的价值。
英文摘要：
Population III (Pop III) stars, the first generation of metal-free stars, remain undetected, partly because entirely pristine galaxies represent a short-lived phase. We instead target the longer-lived self-polluted and hybrid Pop III-Pop II phases, in which surviving metal-free Pop III stars coexist with enriched gas and newly formed Pop II stars, producing strong He II alongside detectable UV metal lines. We search for this signature in 84 strong He II-emitting galaxies at z = 3-7 in the JWST/JADES GOODS-South and GOODS-North fields, combining UV emission-line diagnostics, gas-phase metallicities, AGN screening, and spatially resolved SED fitting. We find no evidence for any pristine Pop III galaxies. Instead, The Blueberry (ID 13176, z = 5.94) is our strongest candidate for a hybrid Pop III-Pop II system and is the only source with robust detections of all diagnostic UV lines. Its resolved stellar populations are extremely young, blue, and weakly attenuated, with high star formation rates, consistent with intense recent star formation. While these properties alone cannot distinguish it from a chemically enriched starburst, its robust UV metal-line ratios provide the strongest evidence in our sample for a surviving Pop III contribution within an enriched host. The Carrot (ID 13577, z = 5.57) further demonstrates the power of resolved analysis, revealing a central region substantially bluer and younger than the galaxy as a whole. Together, these results suggest that Pop III signatures may be spatially localised and diluted in integrated measurements, highlighting resolved SED fitting as a tool for identifying environments where the Universe's first stars may survive.
