CLusters in the Uv as EngineS (CLUES). II. Subkiloparsec-scale Outflows Driven by Stellar Feedback

Abstract

We analyze the far-ultraviolet (1130−1770 Å rest frame) spectroscopy of 20 young (<50 Myr) and massive (>104 M ⊙) star clusters (YSCs) in 11 nearby star-forming galaxies. We probe the interstellar gas intervening along the line of sight, detecting several metal absorption lines of a wide range of ionization potentials, from 6.0 to 77.5 eV. Multiple-component Voigt fits to the absorption lines are used to study the kinematics of the gas. We find that nearly all targets in the sample feature gas outflowing from 30 up to 190 km s−1, often in both the neutral and ionized phases. The outflow velocities correlate with the underlying stellar population properties directly linked to the feedback: the mass of the YSCs, the photon production rate, and the instantaneous mechanical luminosity produced by stellar winds and supernovae. We detect a neutral inflow in four targets, which we interpret as likely not associated with the star cluster but tracing larger-scale gas kinematics. A comparison between the outflows’ energy and that produced by the associated young stellar populations suggests an average coupling efficiency of 10% with a broad scatter. Our results extend the relation found in previous works between galactic outflows and the host galaxy star formation rate to smaller scales, pointing toward the key role that clustered star formation and feedback play in regulating galaxy growth.

Hidden Gems on a Ring: Infant Massive Clusters and Their Formation Timeline Unveiled by ALMA, HST, and JWST in NGC 3351

“…Our Starburst99 simulation suggests that the YMCs can together produce a mechanical luminosity of ∼2 × 10 40 erg s −1 , or a total deposited mechanical energy of ∼3 × 10 54 erg over 4 Myr. A mere 2% energy retention factor (easily reachable for stellar wind and supernova-driven outflows; see Kim et al 2020;Sirressi et al 2024) would be enough to power the ionized gas outflow reported by Leaman et al (2019) and to heat the X-ray emitting gas studied by Swartz et al (2006). These order-of-magnitude calculations suggest that the current population of YMCs will be more than capable of driving gas outflow at a similar level in the future.…”