韦布空间望远镜（JWST）观测到的致密宽线发射源的电离特性

本文研究了红移 $z>4$ 时期的大量宽线发射源，旨在评估除暗星系（faint galaxy）外其他源对宇宙再电离的贡献。通过对韦布空间望远镜（JWST）观测数据的系统普查，研究人员筛选出了一类致密的蓝色宽线发射源，并分析了其光谱与形态特征。结果表明，这些天体具有高温电离连续谱和高电离紫外谱线（UV line），其性质与小红点（Little Red Dots）存在关联。

arXiv:2608.25021v1 Announce Type: new Abstract: The recent JWST discovery of a numerous population of broad-line emitters (BLEs) at $z>4$ has reopened the question of whether sources other than faint galaxies contributed significantly to cosmic reionization. To assess this contribution, we present a systematic census of compact, blue broad-line emitters at $4\leq z\leq7$ selected from the DJA, designed to isolate sources in which the UV continuum and the broad-line emission originate from the same compact physical region. Starting from a parent sample of 4145 galaxies with NIRSpec/PRISM spectroscopy and NIRCam imaging, we apply criteria on broad Ha emission (FWHM$>2000$km s-1, detected at S/N$\geq5$, complete at $L_{Ha,broad}\geq10^{42.7}$erg s-1), blue continuum slopes ($\beta_{UV}\leq-1.5$, $\beta_{opt}<0.5$), and morphological compactness in both the rest-frame UV and optical, returning a final sample of 20 sources. This constitutes $\sim20%$ of the PRISM-selected broad-line sample, which is dominated by Little Red Dots (LRDs). We find that the compact blue BLEs display hot ionizing continua, high-ionization UV lines (CIV, NIV], HeII), and elevated Lya emitter fractions ($X_{Lya}=50-67%$) relative to star-forming galaxies and LRDs. Beyond their similar lack of X-ray emission, their optical spectra closely resemble those of LRDs. This suggests that compact blue BLEs extend this population towards lower column