论文标题
与JWST在Z〜5行动中捕获的大型星系形成
Massive galaxy formation caught in action at z~5 with JWST
论文作者
论文摘要
我们报告了JWST/CEERS调查所涵盖的EGS场中Z〜5.2的紧凑型星系CGG-Z5的发现。在最近的JWST公共调查中，CGG-Z5被选为Z> 2的最高星系密度，它由六名候选人组成，位于预计面积为$ 1.5“ \ times3” $（10 $ \ times $ \ times $ 20〜kpc $^2 $）之内。所有小组成员均为HST/F435W和HST/F606W辍学，同时在JWST/Nircam频段中牢固检测到，产生了狭窄的稳健光度红移$ 5.0 <z <z <5.3 $。组中最庞大的星系具有恒星的质量日志$（m _ {*}/m _ {\ odot}）\ oft9.8 $，而其余的则是低质量卫星（log $（m _ {*}/m _ {\ odot}）尽管已经在HST和IRAC频段中检测到了几个小组成员，但低恒星质量和结构的紧凑性需要JWST的敏感性和分辨率来识别其识别。为了评估CGG-Z5的性质和进化路径，我们在\ textsc {eagle}模拟中搜索了类似的紧凑结构，并随着时间的推移遵循它们的演变。我们发现，所有确定的结构通过z = 3合并为单个星系，并在z〜1形成一个庞大的星系（log $（m _ {*}/m _ {\ odot}）> 11 $）。这意味着CGG-Z5可能是在大型星系形成的短寿命阶段捕获的“原始星系”。
We report the discovery of a compact group of galaxies, CGG-z5, at z~5.2 in the EGS field covered by the JWST/CEERS survey. CGG-z5 was selected as the highest overdensity of galaxies at z>2 in recent JWST public surveys and it consists of six candidate members lying within a projected area of $1.5"\times3"$ (10$\times$20~kpc$^2$). All group members are HST/F435W and HST/F606W dropouts while securely detected in the JWST/NIRCam bands, yielding a narrow range of robust photometric redshifts $5.0<z<5.3$. The most massive galaxy in the group has a stellar mass log$(M_{*}/M_{\odot})\approx9.8$, while the rest are low-mass satellites (log$(M_{*}/M_{\odot})\approx8.4-9.2$). While several group members were already detected in the HST and IRAC bands, the low stellar masses and the compactness of the structure required the sensitivity and resolution of JWST for its identification. To assess the nature and evolutionary path of CGG-z5, we searched for similar compact structures in the \textsc{Eagle} simulations and followed their evolution with time. We find that all the identified structures merge into a single galaxy by z=3 and form a massive galaxy (log$(M_{*}/M_{\odot})>11$) at z~1. This implies that CGG-z5 could be a "proto-massive galaxy" captured during a short-lived phase of massive galaxy formation.
