2025/10/13 by Roy, Namrata, Henry, Alaina, Jones, Tucker +11
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2510.11326
We present spatially resolved rest-optical spectroscopy of 38 star-forming galaxies at 0.5 < z < 1.7 from the JWST/NIRSpec MSA-3D survey, which uses slit-stepping to build IFU-like datacubes at 0.1'' resolution. We map emission-line morphology, excitation, and kinematics of the warm ionized gas using [N II]/Hα, [S II]/Hα, and [O III]/Hβ. Relative to z∼0 galaxies at fixed stellar mass, our sources show systematically lower [N II]/Hα and [S II]/Hα and elevated [O III]/Hβ, consistent with harder radiation fields and lower metallicities. Radially, [O III]/Hβ profiles are typically flat or mildly positive, whereas [N II]/Hα also remains flat or declines outward, mirroring metallicity trends. On kpc scales, we find a strong positive correlation between [N II]/Hα and velocity dispersion (σ), linking local excitation to turbulent or shock-driven kinematics. Six galaxies (∼ 16% of the sample) host spatially localized regions with elevated [N II]/Hα, high EW(Hα), and VRMS = √(V2 + σ2) > 200 km/s, indicative of weak AGN activity, shocks, or outflows. For these candidates we infer modest warm-ionized outflow rates of 1-4 Msun/yr and kinetic powers ∼ 0.1-1% of the AGN bolometric luminosity (from central [O III] or Hα). These values place our sample at the low-energy tail of known AGN-driven outflows yet in continuity with Mout-LAGN scaling relations across 0 < z < 6. A completeness assessment shows MSA-3D is sensitive to AGN with LAGN ≥ 1043 erg/s, underscoring both the promise and current limitations of detecting weak AGN activity in distant galaxies with resolved spectroscopy.