Widespread Star Formation and Ionized Gas Filamentation in Sgr C

The stellar life cycle in the Central Molecular Zone (CMZ), the region within a Galactocentric radius of ~300 parsecs, remains poorly understood. We present James Webb Space Telescope (JWST) near-infrared observations of the CMZ star-forming molecular cloud Sagittarius C (Sgr C) that shed light on this process. JWST reveals outflows, in the form of atomic and molecular hydrogen shocks, from several low- to high-mass protostars widely distributed throughout the cloud. In particular, the inner outflow region of two massive protostars, each with an SED-fit mass of ~20 solar masses, is probed with unprecedented resolution, and corroborated by dust continuum and molecular line data from the ALMA radio observatory. We also report the discovery of a new star-forming region, ~1’ to the west of Sgr C, hosting two prominent bow-shocks driven by at least two actively-forming YSOs. In addition to star formation, we present evidence that the Sgr C HII region, associated with the main star-forming cloud, is evolving under magnetically dominated conditions. Unlike any HII region in the Solar vicinity, the Sgr C plasma displays a remarkably filamentary structure in JWST Brα observations. The brightest of these filaments are also visible in the radio continuum with the ALMA and MeerKAT observatories, and radio spectral index measurements indicate the presence of both thermal free-free and magnetically-stimulated synchrotron emission. We argue that the strong (~1 mG) CMZ magnetic fields have confined the plasma flow in Sgr C to rope-like filaments or sheets, and present radiative magnetohydrodynamic simulations of highly magnetized HII region evolution that support our interpretation. Corroborating this claim on the observational side, we observe a statistically significant peak in the distribution of Brα filament orientations perpendicular to the galactic plane, or along the poloidal component of the global CMZ magnetic field, as well as a plasma β below 1, even in the densest regions. We speculate that all mature HII regions in the CMZ, and galactic nuclei in general, evolve in a magnetically dominated, low plasma β regime, with consequences for our understanding of stellar feedback in extreme environments.