Title: A power spectral study of PHANGS galaxies with JWST MIRI: On the spatial scales of dust and PAHs Show Chinese title

Title: 使用 JWST MIRI 对 PHANGS 星系的功率谱研究：尘埃和 PAH 的空间尺度

Abstract: The interstellar medium (ISM) consists of a diversity of structures across a range of spatial scales, intimately tied to galactic evolution. In this work, Fourier analysis is used to characterize the spatial structures of dust and Polycyclic Aromatic Hydrocarbons (PAHs) in the ISM of PHANGS-JWST galaxies, observed in the four photometric mid-infrared (MIR) filters from F770W to F2100W (i.e., 7.7 to 21$\mu$m)). We quantify the abundance of structure on different spatial scales using the power-law slope, $\alpha$, of the spatial power spectra. The distribution of $\alpha$ across all length scales differs significantly between filters, with steeper slopes for PAH-dominated filters ($\alpha_{F770W} = 2.19^{+0.16}_{-0.15}$, $\alpha_{F1130W} = 1.88^{+0.25}_{-0.37}$) and shallower for the dust-continuum ($\alpha_{F1000W} = 1.48^{+0.33}_{-0.47}$, $\alpha_{F2100W} = 0.94^{+0.23}_{-0.28}$). The distribution of $\alpha$ across galaxies is narrower for PAH-dominated than for thermal dust-dominated bands, highlighting that PAHs trace photo-dissociation regions dominated by similar physical processes, whereas dust structures are an integrated property over the diverse evolutionary histories of their host galaxies. Unlike dust structures, PAH-sensitive bands display a break in the power spectrum: below a characteristic scale, $\ell_0=160\mathrm{pc}^{+110\mathrm{pc}}_{-50\mathrm{pc}}$, PAH structures are suppressed. Show Chinese abstract

Abstract: 星际介质（ISM）由各种各样的结构组成，跨越不同的空间尺度，与星系的演化密切相关。 在这项工作中， 我们使用傅里叶分析来表征 PHANGS-JWST 星系中星际介质中尘埃和多环芳烃（PAHs）的空间结构，这些星系通过从 F770W 到 F2100W 的四个测光中红外（MIR）滤光片观测（即 7.7 至 21$\mu$米）。 我们通过空间功率谱的幂律斜率 $\alpha$来量化不同空间尺度上的结构丰度。 在所有长度尺度上，$\alpha$的分布因滤光片而异，在 PAH 占主导地位的滤光片（$\alpha_{F770W} = 2.19^{+0.16}_{-0.15}$，$\alpha_{F1130W} = 1.88^{+0.25}_{-0.37}$）中斜率更陡，在尘埃连续发射的滤光片（$\alpha_{F1000W} = 1.48^{+0.33}_{-0.47}$，$\alpha_{F2100W} = 0.94^{+0.23}_{-0.28}$）中则较浅。 $\alpha$在星系中的分布对于以PAH为主的波段比以热尘为主的波段更窄，这表明PAHs追踪由相似物理过程主导的光解离区域，而尘埃结构是其宿主星系多样化演化历史的综合属性。 与尘埃结构不同，对PAH敏感的波段在功率谱中显示出一个断裂点：在特征尺度$\ell_0=160\mathrm{pc}^{+110\mathrm{pc}}_{-50\mathrm{pc}}$以下，PAH结构受到抑制。