Speaker
Description
Thanks to the unprecedented sensitivity of JWST/NIRSpec, we are now able to study neutral atomic outflows in massive galaxies at high redshift. By detecting optical resonant lines such as Na D and Ca K, which have long been inaccessible from the ground, we have characterized the velocity and mass outflow rate of the neutral phase for a representative sample of galaxies at z~2, finding that powerful neutral outflows are widespread. Compared to ionized outflows, neutral outflows are slower but carry substantially more mass. To ensure the robustness of these results, we calibrated indirect tracers such as the Na D and Ca K absorption lines against a direct measurement of the hydrogen column density. We also analyzed the physical driver of neutral outflows, finding that AGN feedback is likely involved, at least for the quiescent systems. These recent JWST observations thus enable a direct comparison of multi-phase outflows in massive galaxies at Cosmic Noon to the predictions of numerical models.
