PHANGS-JWST First Results: The Influence of Stellar Clusters on PAHs in Nearby Galaxies

TL;DR

This study compares JWST observations of nearby galaxies with theoretical models to understand how stellar clusters influence PAH emission, revealing that larger, ionized PAHs dominate and advancing interstellar dust research.

Contribution

First JWST-based analysis linking stellar clusters to PAH properties, confirming theoretical models and highlighting the impact of radiation fields on PAH characteristics.

Findings

Observed PAH colors align with models of larger, ionized PAHs.

Data supports the influence of stellar clusters on PAH emission.

Results open new avenues for interstellar dust studies.

Abstract

We present a comparison of theoretical predictions of dust continuum and polycyclic aromatic hydrocarbon (PAH) emission with new JWST observations in three nearby galaxies: NGC 628, NGC 1365, and NGC 7496. Our analysis focuses on a total of 1063 compact stellar clusters and 2654 stellar associations previously characterized by HST in the three galaxies. We find that the distributions and trends in the observed PAH-focused infrared colors generally agree with theoretical expectations, and that the bulk of the observations is more aligned with models of larger, ionized PAHs. These JWST data usher in a new era of probing interstellar dust and studying how the intense radiation fields near stellar clusters and associations play a role in shaping the physical properties of PAHs.