遙遠的太空中有多少星系被塵埃擋住，一直是一個未解之謎，即有多少塵埃
星系在最先進的觀測調查中未被檢測到。詹姆斯·韋伯太空望遠鏡使我們能夠探
測到在中紅外波段具有顯著多環芳香烴（PAH）特徵的微弱紅外星系。多環芳
香烴在中紅外波長範圍內是恆星形成和塵埃特性的寶貴追蹤者。詹姆斯·韋伯太
空望遠鏡宇宙演化早期發布科學（CEERS）領域透過中紅外儀器（MIRI）的六
個光度帶提供了從7.7 到21 微米的波長覆蓋。我們已經確定了由多環芳香烴中紅
外輻射主導的星系，稱為PAH 星系。從我們的多波段光度目錄中，我們選擇了
十個顯示出log(S15/S10) > 0.8 高流量比的多環芳香烴星系。光譜能量分佈擬合
分析表明，這些星系是在z ∼ 1 時總紅外光度為1010 ∼ 1011.5 L⊙ 的恆星形成星
系。多環芳香烴星系的形態在MIRI 分辨率內並未顯示出明顯的主要融合或相互
作用的跡象。它們中的大多數位於z ∼ 1 時的星系主序列上。我們的結果表明，
詹姆斯·韋伯太空望遠鏡可以在紅外線檢測到普通的星形成星系中的多環芳香烴
輻射，而不僅僅是超亮紅外線星系。
I

It has been an unanswered question how many dusty galaxies have been unde-
tected from the state-of-the-art observational surveys. JWST enables us to detect
faint IR galaxies that have prominent polycyclic aromatic hydrocarbon (PAH)
features in the mid-IR wavelengths. PAH is a valuable tracer of star formation
and dust properties in the mid-infrared wavelength. The JWST Cosmic Evolution
Early Release Science (CEERS) fields provide us with wavelength coverage from
7.7 to 21 μm using six photometric bands of the mid-infrared instrument (MIRI).
We have identified galaxies dominated by mid-IR emission from PAHs, termed
PAH galaxies. From our multi-band photometry catalogue, we selected ten PAH
galaxies displaying high flux ratios of log(S15/S10) > 0.8. The SED fitting analysis
indicates that these galaxies are star-forming galaxies with total IR luminosities
of 1010 ∼ 1011.5 L⊙ at z ∼ 1. The morphology of PAH galaxies does not show
any clear signatures of major merging or interaction within the MIRI resolution.
The majority of them are on the star-formation main sequence at z ∼ 1. Our re-
sult demonstrates that JWST can detect PAH emissions from normal star-forming
galaxies at z ∼ 1, in addition to LIRGs/ULIRGs.
II

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