Spectroscopic and interferometric study of NGC 1068's active nucleus in the near-infrared

I present a study of the active nucleus of NGC 1068, archetype of Seyfert 2 galaxies. Using SPHERE and GRAVITY, two near infrared-high angular resolution instruments from the Very Large Telescope, I draw a multi-scale picture of the object. The first part -built around a SPHERE spectroscopic observation- is focused on the study of large-scale structures formed by the stellar populations and the ionized gas region. The study of the continuum emission reveals a uniform presence of hot stars in the region, as well as a central stellar cluster whose age is estimated from a stellar population evolutionary model. The dynamics of the ionised gas is also observed through many emission lines, whose Doppler shift highlights a bipolar wind. The second part -based on a GRAVITY interferometric observation- is dedicated to the study of the inner edge of the torus, where hot dust heated by the central radiation is close to sublimation. I use several methods to interpret and reproduce the observables: geometrical models, image reconstructions, and a physical three dimensional simulation. The most advanced method, which uses the simulation code MontAGN to simulate the radiative transfer and the infrared emission of disk heated by a central source, is able to reproduce correctly all the observables. It provides among other an estimation of the sublimation radius of the structure, its width, its density, its three dimension orientation, its density and the foreground extinction. The orientation of the structure, which is not observed edge-on and does not obscure the central source, is surprising, in regard to both the well-known obscured nature of the nucleus and the direct measurement of the orientation of structures similar scale. This result may be explained by the presence of warped disk or a system of intricated rings with different observations. (author)