The Hidden Life of Stars: Embedded Beginnings to Asymptotic Giant Branch Endings in the PHANGS–JWST Sample. I. Catalog of Mid-infrared Sources

Abstract We present a multiwavelength catalog of mid-infrared-selected compact sources in 19 nearby galaxies, combining JWST NIRCam/MIRI, Hubble Space Telescope UV–optical broadband, H α narrowband, and Atacama Large Millimeter/submillimeter Array CO observations. We detect 24,945 compact sources at 21 μ m and 55,581 at 10 μ m. Artificial star tests show 50% completeness limits of ∼5 μ Jy for the 10 μ m catalog, and ∼24 μ Jy for the 21 μ m catalog. We find that 21 μ m compact sources contribute ∼20% of the total galaxy emission in that band, but only contribute 5% at 10 μ m. We classify sources using stellar evolution and population synthesis models combined with empirical classifications derived from the literature. Our classifications include H α -bright and dust-embedded optically faint clusters, red supergiants, oxygen-rich and carbon-rich asymptotic giant branch stars, and a range of rarer stellar types. In sampling a broad range of star-forming environments with a uniform, well-characterized selection, this catalog enables analyses of infrared-bright stellar populations. We find that H α -faint sources account for only 10% of dusty (likely young) clusters, implying that the infrared-bright, optically faint phase of cluster evolution is short compared to the H α -bright stage. The luminosity functions of 10 and 21 μ m sources follow power-law distributions, with the 21 μ m slope (−1.7 ± 0.1) similar to that of giant molecular cloud mass functions and ultraviolet bright star-forming complexes, while the 10 μ m slope (−2.0 ± 0.1) is closer to that of young stellar clusters.