The Resolved Behavior of Dust Mass, Polycyclic Aromatic Hydrocarbon Fraction, and Radiation Field in ∼800 Nearby Galaxies

• Published in: The Astrophysical journal. Supplement series 2025-01, Vol.276 (1), p.2
• Main Authors: Chastenet, Jérémy, Sandstrom, Karin, Leroy, Adam K., Bot, Caroline, Chiang, I-Da, Chown, Ryan, Gordon, Karl D., Koch, Eric W., Roussel, Hélène, Sutter, Jessica, Williams, Thomas G.
• Format: Article
• Language: English
• Subjects: Correlation; Cosmic dust; Density; Dust; Galaxies; Galaxy distribution; H II regions; Infrared astronomy; Infrared photometry; Interstellar dust; Interstellar radiation; Metallicity; Polycyclic aromatic hydrocarbons; Radiation; Spectral energy distribution; Star & galaxy formation; Star formation; Star formation rate; Stars; Stellar mass
• ISSN: 0067-0049; 1538-4365
• DOI: 10.3847/1538-4365/ad8a5c

We present resolved 3.6–250 μm dust spectral energy distribution (SED) fitting for ∼800 nearby galaxies. We measure the distribution of radiation field intensities heating the dust, the dust mass surface density (Σd), and the fraction of dust in the form of polycyclic aromatic hydrocarbons (PAHs; qPAH). We find that the average interstellar radiation field (U¯) is correlated both with stellar mass surface density (Σ⋆) and star formation rate surface density (ΣSFR), while more intense radiation fields are only correlated with ΣSFR. We show that qPAH is a steeply decreasing function of ΣSFR, likely reflecting PAH destruction in H ii regions. Galaxy-integrated qPAH is strongly, negatively correlated with specific star formation rate (sSFR) and offset from the star-forming “main sequence” (ΔMS), suggesting that both metallicity and star formation intensity play a role in setting the global qPAH. We also find a nearly constant Md/M* ratio for galaxies on the main sequence, with a lower ratio for more quiescent galaxies, likely due to their lower gas fractions. From these results, we construct prescriptions to estimate the radiation field distribution in both integrated and resolved galaxies. We test these prescriptions by comparing our predicted U¯ to results of SED fitting for stacked “main-sequence” galaxies at 0 < z < 4 from M. Béthermin et al. and find sSFR is an accurate predictor of U¯ even at these high redshifts. Finally, we describe the public delivery of matched-resolution Wide-field Infrared Survey Explorer and Herschel maps along with the resolved dust SED-fitting results through the Infrared Science Archive.