PHANGS–JWST First Results: Stellar-feedback-driven Excitation and Dissociation of Molecular Gas in the Starburst Ring of NGC 1365?

Abstract We compare embedded young massive star clusters (YMCs) to (sub-)millimeter line observations tracing the excitation and dissociation of molecular gas in starburst ring NGC 1365. This galaxy hosts one strongest nuclear starbursts richest populations YMCs within 20 Mpc. Here we combine near-/mid-IR PHANGS–JWST imaging with new Atacama Large Millimeter/submillimeter Array multi- J CO (1–0, 2–1 4–3) [ C i ] (1–0) mapping, which use trace via R 42 = I CO(4−3) / CO(2−1) 21 CO(1−0) CICO [CI](1−0) at 330 pc resolution. find that flowing into from northeast southwest appears strongly affected by stellar feedback, showing decreased (lower ) increased signatures (higher downstream regions. There, radiative-transfer modeling suggests density decreases temperature [CI/CO] abundance ratio increase. local conditions across regions both correlate near-IR 2 μ m emission polycyclic aromatic hydrocarbon (11.3 m) dust continuum (21 emission. In general, exhibits ∼0.1 dex tighter correlations than , suggesting be a more sensitive tracer changing physical 1365 (4–3). Our results are consistent scenario where flows two arm along bar, becomes condensed/shocked, forms YMCs, then these heat dissociate gas.