2025/08/13 by Congcong Zhang, Joelene Hales, E. Peeters +3 · 1 voice
Physics and Astronomy · #Astrophysics and Star Formation Studies #Scientific Research and Discoveries #Galaxies: Formation, Evolution, Phenomena
paper · doi:10.3847/1538-4365/adea6b
openalex publication_date 2025/08/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Polycyclic aromatic hydrocarbons (PAHs) are responsible for strong mid-IR emission features near star-forming regions. It is well known that low-metallicity environments exhibit weaker PAH emission, but it is not clear how metallicity affects the properties of the emitting PAH population. We present a detailed study of the PAH emission in a region of 30 Doradus (30 Dor), a well-known low-metallicity star-forming environment in the Large Magellanic Cloud and we compare it to PAH emission in the Orion Bar to investigate the characteristics of the PAH population and how the environments affect the resulting IR emission. We analyze JWST observations of 30 Dor that include imaging (NIRCam and MIRI) and spectroscopy (NIRSpec integral-field unit (IFU) and MIRI Medium Resolution Spectroscopy (MRS)). We extracted NIRSpec/IFU and MIRI/MRS spectra from 18 apertures that cover the morphological structures present within the observed region of 30 Dor. We characterize the profiles and relative intensities of PAH emission in these apertures. The detailed profiles of the PAH emission bands in 30 Dor are all similar and match with one of the dissociation fronts (DF2) in the Orion Bar, but their relative band ratios show a much larger range than in the Orion Bar. The PAH emission in 30 Dor originates from a population with a lower or similar ionization fraction than in the Orion Bar, and a size distribution that has more small-sized PAHs. Since smaller PAHs typically photofragment before larger PAHs, our findings support the hypothesis that the lower PAH emission due to lower metallicities is the result of the inhibition of growth toward larger PAHs rather than photofragmentation.