Variations in the 3.3 μm Polycyclic Aromatic Hydrocarbon Feature Across Nearby Galaxies Driven by Metallicity and Radiation Field Spectrum

@misc{koziol2026variations,
  title = {{Variations in the 3.3 $μ$m Polycyclic Aromatic Hydrocarbon Feature Across Nearby Galaxies Driven by Metallicity and Radiation Field Spectrum}},
  author = {Hannah B. Koziol and Karin Sandstrom and Dalya Baron and Adam K. Leroy and Jérémy Chastenet and Ryan Chown and Daniel A. Dale and Oleg V. Egorov and Lindsey Hands and Mansi Padave and Debosmita Pathak and Erik Rosolowsky and Jessica Sutter and Tony D. Weinbeck and Thomas G. Williams and Alberto Bolatto and Médéric Boquien and Yixian Cao and Enrico Congiu and Simon C. O. Glover and Hwihyun Kim and Ralf S. Klessen and Kirsten L. Larson and Justus Neumann and Elias K. Oakes and Hsi-An Pan and Ismael Pessa and Sumit K. Sarbadhicary and Benjamin W. Stadel and Jiayi Sun and David A. Thilker and Leonardo Úbeda},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2608.05286},
  eprint = {2608.05286},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.05286},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Variations in the 3.3 μm Polycyclic Aromatic Hydrocarbon Feature Across Nearby Galaxies Driven by Metallicity and Radiation Field Spectrum
AU  - Hannah B. Koziol
AU  - Karin Sandstrom
AU  - Dalya Baron
AU  - Adam K. Leroy
AU  - Jérémy Chastenet
AU  - Ryan Chown
AU  - Daniel A. Dale
AU  - Oleg V. Egorov
AU  - Lindsey Hands
AU  - Mansi Padave
AU  - Debosmita Pathak
AU  - Erik Rosolowsky
AU  - Jessica Sutter
AU  - Tony D. Weinbeck
AU  - Thomas G. Williams
AU  - Alberto Bolatto
AU  - Médéric Boquien
AU  - Yixian Cao
AU  - Enrico Congiu
AU  - Simon C. O. Glover
AU  - Hwihyun Kim
AU  - Ralf S. Klessen
AU  - Kirsten L. Larson
AU  - Justus Neumann
AU  - Elias K. Oakes
AU  - Hsi-An Pan
AU  - Ismael Pessa
AU  - Sumit K. Sarbadhicary
AU  - Benjamin W. Stadel
AU  - Jiayi Sun
AU  - David A. Thilker
AU  - Leonardo Úbeda
PY  - 2026
DA  - 2026/10/27
PB  - arXiv
DO  - 10.48550/arxiv.2608.05286
UR  - https://arxiv.org/abs/2608.05286
AB  - We use JWST NIRCam imaging to investigate the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature in nearby galaxies. NIRCam observations of the 3.3 μm feature are emerging as a powerful tool for studying the structure of the interstellar medium (ISM) and the conditions of the dust at ~0".1 resolution. These maps require accurate subtraction of the underlying continuum emission. We present an empirical method to isolate the PAH-correlated emission in the F335M filter using the F300M and F360M filters for continuum subtraction. We find that the slope of the F335M/F300M versus F360M/F300M colors for PAH-correlated emission shows a dependence on local ISM properties, with the strongest dependence on specific star formation rate. Weaker emission features captured by these bands appear suppressed relative to the main 3.3 μm feature in regions of active star formation. We find trends in the 3.3/7.7 and 3.3/11.3 μm ratios that suggest changes in PAH size, charge, and heating by a varying radiation field spectrum. We find decreases in both band ratios with increasing metallicity, which we attribute to a shift to smaller PAH populations at low metallicity. Comparison to optical ionized gas line ratios and dust models show that variations in the interstellar radiation field spectrum influence the PAH feature ratios. This analysis supports inhibited growth formation scenarios for the observed PAH band ratio trends with metallicity and emphasizes the importance of considering the local radiation field characteristics and gas-phase metallicity when using these band ratios as PAH property diagnostics.
ER  -