窄带选选的莱曼α发射体在z=2-7的红移静止系紫外和光学结构演化：基于JWST/NIRCam观测
Rest-Frame UV and Optical Structural Evolution of Narrowband-Selected Lyman-alpha Emitters at z = 2-7 with JWST/NIRCam
- National Astronomical Observatory of Japan（日本国立天文台）
- The University of Tokyo（东京大学）
- Nara Prefectural University（奈良县立大学）
- The Graduate University for Advanced Studies（综合研究大学院大学）
- Tohoku University（东北大学）
- EPFL（洛桑联邦理工学院）
- Alma Mater Studiorum Università di Bologna（博洛尼亚大学）
- INAF–Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）
- Universität Heidelberg（海德堡大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用JWST/NIRCam数据分析z=2-7的Lyα发射体形态，发现其尺寸随红移演化，光学尺寸与质量关系与恒星形成星系一致，致密源更利于Lyα逃逸。
AI中文摘要：
我们利用来自COSMOS-Web巡天的JWST/NIRCam成像数据，对SILVERRUSH多窄带星表中z≈2-7的Lyα发射体（LAEs）的静止系紫外（UV）和光学形态进行了系统研究。我们在四个NIRCam滤光片（F115W、F150W、F277W、F444W）中对跨越约2.2 Gyr宇宙时间的LAEs拟合了Sérsic轮廓。LAE的尺寸从静止系紫外到光学波长呈现轻微增大，其中光学与紫外尺寸比的中值为$R_{e,\rm opt}/R_{e,\rm UV} = 1.14^{+0.01}_{-0.02}$，表明存在较小的形态学K-修正；该偏移在z≤5.7时显著，但在z=6.6时不显著。静止系光学尺寸遵循幂律演化，由$R_e \propto (1+z)^{-0.94 \pm 0.09}$给出，从z=2.2时的$0.91^{+0.07}_{-0.07}$ kpc减小到z≳5时的约0.5 kpc，这与最近一项关于光谱确认的LAEs的JWST研究结果密切一致。静止系光学尺寸-质量关系的斜率与一般恒星形成星系（SFG）群体的斜率大体一致，而LAEs在z~3-6范围内的归一化水平低于该关系。更致密的LAEs倾向于表现出更高的Lyα等效宽度，这一趋势主要由最致密、勉强分辨的源驱动。这些致密系统还占据较高的恒星形成面密度区域，这与集中恒星形成可能促进Lyα逃逸的情景一致。在z≈2-7范围内，未发现LAE静止系光学尺寸与投影的大尺度环境之间存在显著相关性，这表明LAE的形态可能主要由星系内部性质决定，除非在极端的过度密度区域。
英文摘要：
We present a systematic study of the rest-frame ultraviolet (UV) and optical morphologies of Ly$α$ emitters (LAEs) at $z \simeq 2$-$7$ from the SILVERRUSH multi-narrowband catalog, using JWST/NIRCam imaging from COSMOS-Web. We fit Sérsic profiles in four NIRCam filters (F115W, F150W, F277W, F444W) for LAEs spanning $\sim 2.2$ Gyr of cosmic time. LAE sizes show a mild increase from rest-frame UV to optical wavelengths, with a median optical-to-UV size ratio of $R_{e,\rm opt}/R_{e,\rm UV} = 1.14^{+0.01}_{-0.02}$, indicating a small morphological $K$-correction; this offset is significant at $z \leq 5.7$ but not at $z = 6.6$. The rest-frame optical sizes follow a power-law evolution, given by $R_e \propto (1+z)^{-0.94 \pm 0.09}$, decreasing from $0.91^{+0.07}_{-0.07}$ kpc at $z = 2.2$ to $\sim 0.5$ kpc at $z \gtrsim 5$, in close agreement with a recent JWST study of spectroscopically confirmed LAEs. The rest-frame optical size-mass relation slopes are broadly consistent with those of the general star-forming galaxy (SFG) population, while LAEs lie below it in normalization over $z \sim 3$-$6$. More compact LAEs tend to exhibit higher Ly$α$ equivalent widths, a trend driven mainly by the most compact, marginally resolved sources. These compact systems also occupy elevated SFR surface-density regimes, consistent with a scenario in which concentrated star formation may facilitate Ly$α$ escape. No significant correlation of LAE rest-frame optical size with projected large-scale environment is found over $z \simeq 2$-$7$, suggesting that LAE morphology may be governed primarily by internal galaxy properties, except possibly in the most extreme overdensities.
