GA-NIFS: NIRSpec reveals evidence for non-circular motions and AGN feedback in GN20

Hannah Übler; Francesco D'Eugenio; Michele Perna; Santiago Arribas; Gareth C. Jones; Andrew J. Bunker; Stefano Carniani; Stéphane Charlot; Roberto Maiolino; Bruno Rodríguez del Pino; Chris J. Willott; Torsten Böker; Giovanni Cresci; Nimisha Kumari; Isabella Lamperti; Eleonora Parlanti; Jan Scholtz; Giacomo Venturi

arXiv · 2403.03192

GA-NIFS: NIRSpec reveals evidence for non-circular motions and AGN feedback in GN20

Hannah Übler·Francesco D'Eugenio·Michele Perna·Santiago Arribas·Gareth C. Jones·Andrew J. Bunker·Stefano Carniani·Stéphane Charlot·Roberto Maiolino·Bruno Rodríguez del Pino·Chris J. Willott·Torsten Böker·Giovanni Cresci·Nimisha Kumari·Isabella Lamperti·Eleonora Parlanti·Jan Scholtz·Giacomo Venturi

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Abstract

We present rest-frame optical data of the z~4 sub-millimeter galaxy GN20 obtained with JWST/NIRSpec in integral field spectroscopy (IFS) mode. The H$α$ emission is asymmetric and clumpy and extends over a projected distance of more than 15 kpc. To first order, the large-scale ionised gas kinematics are consistent with a turbulent ($σ\sim90$ km/s), rotating disc ($v_{\rm rot}\sim500$ km/s), congruent with previous studies of its molecular and ionised gas kinematics. However, we also find clear evidence for non-circular motions in the H$α$ kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion or radial flows. In the centre of GN20, we find broad line emission (FWHM $\sim1000-2000$ km/s) in the H$α$+[N II] complex, suggestive of fast, AGN-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N II]$\lambda6583$/H$α>0.4$ and EW(H$α)>6$ Å, throughout large parts of GN20 suggest that feedback from the active black hole is able to photo-ionise the interstellar medium. Our data corroborates that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago.

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Hannah Übler, Francesco D'Eugenio, Michele Perna, Santiago Arribas, Gareth C. Jones, Andrew J. Bunker, Stefano Carniani, Stéphane Charlot, Roberto Maiolino, Bruno Rodríguez del Pino, Chris J. Willott, Torsten Böker, Giovanni Cresci, Nimisha Kumari, Isabella Lamperti, Eleonora Parlanti, Jan Scholtz, Giacomo Venturi. 2024-08-22. GA-NIFS: NIRSpec reveals evidence for non-circular motions and AGN feedback in GN20. https://arxiv.org/abs/2403.03192

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