Abstract

Massive, starbursting galaxies in the early Universe represent some of the most extreme objects in the study of galaxy evolution. Studies of their FIR emission with ALMA /NOEMA have revealed immense molecular gas reservoirs, high levels of star formation activity, and evidence for complex kinematics (e.g., rotation, merging, outflows). With the advent of the JWST /NIRSpec IFU , we may now investigate the ionised gas properties and kinematics on sub-kpc scales. Here, we detail the study of three such sources from the GA-NIFS survey: the SMG HFLS3 (z=6.34), the FIR -bright source HZ10 (z=5.65), and the LBG B1465666 (z=7.15). Using new NIR Spec/IFU data we present spectral fits, morpho-kinematic maps, and line ratio analyses for each. All sources are resolved into multiple discrete components, with spatial variations in ISM conditions that are explored through comparison to FIR observations.