GA-NIFS: high prevalence of dusty and metal-enriched outflows in massive and luminous star-forming galaxies at $z\sim3-9$

B. Rodríguez Del Pino, S. Arribas, M. Perna, I. Lamperti, A. Bunker, S. Carniani, S. Charlot, F. D'Eugenio, R. Maiolino, H. Übler, E. Bertola, T. Böker, G. Cresci, G. C. Jones, C. Marconcini, E. Parlanti, J. Scholtz, G. Venturi, S. Zamora

First listed 2026-01-09 | Last updated 2026-01-09

Abstract

We present a search for and characterization of ionized outflows in 15 star-forming systems at $z\sim3-9$ with no evidence of Active Galactic Nuclei (AGN), observed with JWST/NIRSpec IFU as part of the GA-NIFS program. The targets often show satellites and complex substructure, from which we isolate 40 galaxies/regions. The sample probes the high-mass end of the galaxy population, with most sources having log$_{10}$~(M$_\star$/M$_\odot$)=$9.5-11$, extending previous studies on high-z star formation driven outflows that mainly focused on lower-mass galaxies. Using the [OIII]5007 and H$α$ emission lines, we identify broad kinematic components consistent with galactic outflows in 14 galaxies/regions. We find that the outflowing gas is more dust attenuated (by $A_{\rm V}$$\sim0.59$ mag on average) and metal-enriched (0.13 dex) than the interstellar medium (ISM) of the host galaxies, but its velocities are insufficient to escape the galaxies and reach the circumgalactic medium, suggesting that outflows mainly redistribute dust and metals around their hosts. The outflows identified in this study display velocity dispersions within $σ_{\rm out}=130-340$~km~s$^{-1}$ and outflow velocities $v_{\rm out}=170-600$~km~s$^{-1}$, and, when combined with less luminous and less massive star-forming galaxies from previous works, reveal a statistically significant correlation between $v_{\rm out}$ and star formation rate (SFR). The typically low mass-loading factors ($η=\dot{M}_{\rm out}/SFR$$\leq1$, in 9 out of 14 the outflows) indicate that these outflows do not strongly suppress star formation. Overall, our results suggest that ejective feedback via ionized outflows is inefficient in massive, luminous star-forming galaxies within the first 2 Gyr of the Universe.

Short digest

JWST/NIRSpec IFU data from GA-NIFS targets 15 massive, luminous star-forming systems at z≈3–9 (split into 40 galaxies/regions) with no AGN and searches for ionized outflows via [O III]5007 and Hα line profiles. Broad components signal outflows in 14 galaxies/regions with σout=130–340 km s−1 and vout=170–600 km s−1; the outflowing gas is dustier (ΔAV≈0.59 mag) and more metal-enriched (+0.13 dex) than the host ISM. Typical vout fall below escape speeds and mass-loading factors are low (η≤1 in 9/14), implying weak suppression of star formation. Combined with lower-mass samples, vout correlates with SFR, pointing to early massive SFG outflows that primarily redistribute dust and metals locally rather than evacuate them to the CGM.

Key figures to inspect

• Line-profile decompositions of [O III]5007 and Hα showing narrow+broad components for representative regions—use these to verify the detection fraction (14/40) and read off σout and vout ranges.
• Maps comparing AV and metallicity for the broad (outflow) versus systemic components—inspect spatial offsets and quantify the ΔAV≈0.59 mag and +0.13 dex enrichment of the outflowing gas.
• vout versus SFR relation combining GA-NIFS with literature lower-mass samples—check slope, scatter, and how these high-mass, luminous systems extend the trend.
• vout (or vout/vesc) compared to host escape velocities—assess what fraction cannot escape and how gravitational potential shapes retention.
• Mass-loading factor (η) versus M⋆ or SFR—confirm that most η values lie ≤1 and evaluate the implication for feedback-driven quenching.