2025/12/10 by Giacomo Venturi, Stefano Carniani, Venturi, Giacomo +45
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies
paper · pdf · doi:10.1051/0004-6361/202558509
The period between z ∼ 3-6 (`cosmic morning'), a key transformational phase in galaxy evolution preceding `cosmic noon' (z ∼ 1-3), is very poorly explored in terms of feedback from active galactic nuclei (AGN) acting through gas outflows driven by energetic radiation. In this work, we study the properties of outflows in AGN (mostly X-ray-selected) from the GOODS-S field, exploiting JWST NIRSpec IFU observations as part of the Galaxy Assembly with NIRSpec IFS (GA-NIFS) GTO survey. Together with its twin subsample from the COSMOS field reported in a previous GA-NIFS work, this constitutes the largest spatially resolved sample of AGN outflows at these redshifts to date, comprising 16 targets with outflows (out of a total of 19 AGN), and probes the unexplored regime of AGN at z ∼ 3-6 with bolometric luminosities of łbol ∼ 10^ 45-46 We mapped the rest-frame optical ionised gas emission lines (e.g. at sub-kiloparsec scales and spectrally isolated the broad wings that trace fast outflows from the gas at rest in the host galaxies. The incidence of ionised outflows in the GOODS-S + COSMOS GA-NIFS sample is high (>75%), among the highest at any redshift; however, a more homogeneous outflow detection method and sample selection would be required to draw firm conclusions on the redshift evolution of the outflow incidence. We inferred outflow velocities between ∼600--2000 ̨ms, maximum radii of łesssim1 up to ∼4 kpc, and ionised gas mass outflow rates of ∼0.1 up to ≳100 which in some cases can exceed the host galaxy star formation rate (SFR). The assumed electron density of 1000 cm -3 is conservative; lower values, as measured in some outflow studies and suggested by theory, would imply inversely proportionally higher mass outflow rates. We find that the outflow properties inferred for the GOODS-S + COSMOS GA-NIFS AGN sample and their relations to łbol and SFR generally align with those observed for other spatially resolved literature samples of AGN outflows across different redshifts and AGN luminosities. Nonetheless, after accounting for any luminosity bias, our analysis suggests a cosmic evolution of the outflow properties, with higher median mass outflow rates (and possibly also mass loading factors) at higher redshifts, especially at z>3, which indicates that AGN outflows were stronger in the early Universe than at later times, and thus potentially more capable of affecting their host galaxy.