JWST MIRI-MRS Maps 11.5 pc Young Bubble in NGC 253 Driven by 10^6 Solar Mass Cluster

Multi-wavelength data combine new JWST MIRI-MRS maps of ionized and molecular lines with archival ALMA CO transitions at 100, 350 and 690 GHz plus Chandra X-ray imaging. The bubble coincides with one of the least embedded ALMA-detected clusters, allowing RADEX modeling to constrain molecular gas mass between 1.3e4 and 2.8e5 solar masses. Expansion velocity and radius measurements yield a mechanical energy input consistent with Wolf-Rayet winds or early supernovae from a roughly 10^6 solar mass cluster.

This detection supplies direct evidence that individual clusters in dense nuclear environments can excavate parsec-scale cavities and inject momentum into the interstellar medium, contributing to the larger-scale molecular outflow previously mapped in NGC 253. Earlier ground-based and Spitzer studies inferred collective feedback from the starburst but lacked the spatial resolution to isolate single-cluster driving. The new data bridge that gap and align with hydrodynamic simulations showing that clustered feedback can sustain nuclear winds without requiring distributed supernovae.

Future ALMA and JWST observations targeting additional bubbles and higher-J CO lines will test whether this mechanism scales across the nuclear disk. Refined proper-motion measurements could tighten the expansion age to better than 0.05 Myr within the next two years.