colloquium – Michele Perna: First results from the JWST GTO programme ‘Galaxy Assembly with NIRSpec IFS’ (GA-NIFS): The gaseous environment and ISM properties of quasars at z = 3-7

The JWST/NIRSpec GTO programme ‘Galaxy Assembly with NIRSpec IFS’ (GA-NIFS) is an ambitious project aimed at characterising the internal structure of >40 distant galaxies and active galactic nuclei (AGN) and quasars (QSOs) at z=3-9, and, therefore, to investigate the primary physical processes driving galaxy evolution across cosmic time. In this talk I will present an overview of the very first results obtained from a subsample of QSOs, as well as the analysis and the knowledge on optimising the QSO-host decomposition in NIRSpec IFS data (Perna et al. 2023, Marshall et al. 2023, Übler et al. 2023).

I will discuss the interacting environment of two QSOs at z~6.8 and one at z~5.5, as well as the ultra-dense environment of a dual AGN at z~3.3. I will also present their interstellar medium properties, in terms of dynamical conditions, ionisation, metallicity, and outflows energetics. In particular, I will discuss the limitations of classical emission line diagnostics to distinguish between AGN and star formation ionisation source, and the relation between black hole masses and host galaxy properties in the context of other recent JWST results on high-z QSOs.