Master Thesis Defense by Freja Amalie Nørby

Title: Stellar and Gas Kinematics in Active Galactic Nuclei

Abstract:
This thesis investigates the stellar and ionised gas kinematics of the barred Seyfert galaxy NGC 3783. Using integral field data from MUSE in both Wide and Narrow Field Mode, and high-resolution HST photometry, I derive the stellar and gas dynamics across the field of view using full spectral fitting techniques. I find the ionisation mechanisms in the field of view and find evidence of a strong shock and AGN-driven ionisation field in the central bulge. The Hα and O[III] emission line velocity fields show arms of gas travelling away from the AGN, and high velocity dispersion perpendicular to the galactic bar’s position angle in the centre. These results support a scenario where the bar facilitates central gas inflow, while AGN feedback drives ionised gas outflows in a direction misaligned with the stellar disk, highlighting the complex interplay between galactic structure and nuclear activity. The bar pattern speed is found to be 42.5 km/s/kpc in agreement with the literature. I also detect deviation in the light-weighted ⟨V ⟩/⟨x⟩ that could indicate a secondary inner decoupled bar, which is also consistent with signatures in the narrow emission-line kinematics. I then lay the groundwork for future dynamical modelling to constrain the central black hole mass and better understand feedback mechanisms in barred AGN-host galaxies.

Supervisor: Marianne Vestergaard
Censor: Hans Kjeldsen