GLIMPSED: Direct evidence for a fast AGN-driven outflow from a z=6.64 Little Red Dot host galaxy

Damien Korber, Rui Marques-Chaves, Daniel Schaerer, Gabriel Brammer, Archana Aravindan, Arghyadeep Basu, Qinyue Fei, Emma Giovinazzo, Vasily Kokorev, Alberto Saldana-Lopez, Maxime Trebitsch, Hakim Atek, John Chisholm, Ryan Endsley, Seiji Fujimoto, Lukas Furtak, Richard Pan, Rohan P. Naidu

First listed 2026-04-09 | Last updated 2026-04-09

Abstract

We report the discovery of GLIMPSED-329380, a z=6.64 galaxy behind Abell S1063, which shows signs of an extreme ionised outflow driven by an active galactic nucleus (AGN). The deep JWST/NIRSpec medium grating observations show spatially resolved structures of a host galaxy containing the very fast outflow and an AGN, which we analyse separately. The outflow, mainly traced by broad [O III]λ5008 and Hα emissions in the host, reaches a full-width half-maximum velocity of ~5500km/s, velocities only observed in AGN-dominated systems. From the Balmer decrement, we observe that while the narrow emission lines show no dust attenuation, the outflowing gas is dusty. We use emission lines diagnostics to infer gas abundances within the host galaxy. The oxygen abundance is 12+log(O/H) ~ 7.95 (~18% solar) and the host is slightly nitrogen-enriched with log(N/O) ~ -0.75. Despite its extreme velocity, the mass loading factor (<0.1) and the kinematic energy of the outflow (~10^43 erg/s) suggest limited impact on star formation. The AGN component shows many similarities with little red dots (LRDs): a characteristic "V-shape", exponential profile in hydrogen lines, numerous detection of forbidden [Fe II] lines, a Balmer break, and a broad absorption feature at ~4550 Å. This detection of a fast outflow in an LRD, rare in surveys dominated by low-resolution (e.g. PRISM) spectra, provides direct evidence of AGN activity in these systems.

Short digest

This paper presents direct evidence for a fast AGN-driven outflow in the host galaxy of a z = 6.64 little red dot. The main result is that spatially resolved spectroscopy isolates a very high-velocity outflow component associated with the AGN rather than with ordinary star formation. The paper matters because it ties the LRD phenomenon to concrete feedback physics in the host galaxy rather than only to spectral oddities near the nucleus.

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