AI 中文总结
研究NGC 628中恒星形成复合体里PAH、UV、Hα发射的空间相关性，用詹姆斯·韦布空间望远镜等设备观测，分析PAH光度与其他光度及IMF指数α2的关系，发现PAH波段比率与IMF、颜色有关，不同区域SFCs的IMF表现有差异。
AI 中文摘要
我们研究了NGC 628不同区域恒星形成复合体（SFCs）中多环芳烃（PAH，3.3μm、7.7μm和11.3μm）发射与远紫外（FUV）、近紫外（NUV）和Hα发射的空间相关性。利用詹姆斯·韦布空间望远镜探测PAH发射，紫外成像望远镜和多单元光谱探测器分别对UV和Hα发射进行采样。研究提取的SFCs中PAH光度与FUV、NUV和Hα光度的相关性。发现除仅发射NUV的区域外，旋臂和分支SFCs显示明亮的PAH发射，主要位于气泡和超气泡中。还在幻影空洞（NGC 628中最大的超气泡）中研究了这些相关性。研究FUV - NUV趋势以及从B星与PAH波段比率（F335M/F1130W、F770W/F1130W和F335M/F770W）得出的初始质量函数（IMF）指数α2。发现随着IMF变得更重顶且SFCs变得更蓝，PAH波段比率增加，这与较强紫外辐射场中PAH激发和电离增强一致。然而，分支SFCs的α2与旋臂相比，随PAH波段比率呈平稳趋势。仔细研究发现，幻影空洞壳区域的两个SFCs与细长气泡附近的SFC相比，IMF更平缓。这可能是由于壳区域的气体积累，可能通过反馈机制，而细长气泡附近的SFC可能在受剪切影响的区域形成。
英文摘要
We examine the spatial correlation of emission from polycyclic aromatic hydrocarbons (PAH) (3.3 $μ$m, 7.7 $μ$m, and 11.3 $μ$m) with the far-ultraviolet (FUV), near-ultraviolet (NUV), and H$α$ emission from star-forming complexes (SFCs) in different regions of NGC 628. We use the James Webb Space Telescope to detect PAH emission, along with the Ultraviolet Imaging Telescope and Multi Unit Spectroscopic Explorer observations to sample the UV and H$α$ emission, respectively. We investigate the correlation of PAH luminosities with FUV, NUV, and H$α$ luminosities for the extracted SFCs. We find that the arm and spur SFCs show bright PAH emission, except for those with only NUV emission, located primarily in bubbles and superbubbles. We also examine these correlations in the phantom void, the largest superbubble in NGC 628. We investigate the trend for FUV-NUV and the Initial mass function (IMF) index $α_2$ derived from the ratio of B stars with PAH band ratios (F335M/F1130W, F770W/F1130W, and F335M/F770W). We find that PAH band ratios increase as the IMF becomes more top-heavy and the SFCs become bluer, consistent with enhanced PAH excitation and ionisation in stronger UV radiation fields. However, $α_2$ of spur SFCs shows a flat trend with PAH band ratios compared to arms. Upon closer examination, two SFCs in the shell region of the phantom void showed a flatter IMF compared to the SFC located near the elongated bubble. This is likely due to gas accumulation, possibly through feedback mechanisms in the shell region, while the SFC near the elongated bubble may have formed in a region affected by shear.
CommentsAccepted for publication in MNRAS. 15 pages, including references and appendix, 11 figures
