Galaxies are observed as projected two-dimensional distributions of light, while the physical questions we wish to answer concern their intrinsic structure, orbital composition, and time-dependent formation history. This makes the interpretation of galaxy observations an inherently ill-posed reconstruction problem: from a single viewing angle, affected by resolution, projection effects, dust attenuation, gas emission, nuclear activity, and modelling degeneracies, we try to infer the physical nature of complex galactic systems.
In this talk, I will discuss how spatially resolved observations, combined with techniques such as spectral synthesis, gas-emission modelling, kinematic extraction, and dynamical modelling, can be used to disentangle stellar populations, ionised gas, dust effects, and orbital structure in nearby disk galaxies. Particular attention will be given to bulges, disks, and bars, not as simple or isolated components, but as composite systems that form and evolve together. Their stellar content includes multiple orbital families (i.e., cold, warm, hot, and counter-rotating) as well as stellar populations with different ages and metallicities. This complexity challenges traditional structural decompositions based on assumptions that are often convenient, but not necessarily physically demonstrated.
The central theme will be the spatially varying physical characteristics of galaxies: old or star-formation-quenched central regions may coexist with actively star-forming disks, while compact nuclear activity or young stellar clusters can drive galaxy-wide gas outflows expanding with hundreds of km/s out to the galactic halo. Cosmological simulations provide an important test-bed for this effort: they are time-resolved and reproduce observed galaxy properties, allowing projected observational diagnostics to be tested against the underlying chemodynamical formation history. Ultimately, my goal is to use all these techniques to address fundamental questions on galaxy formation and evolution, while developing physically motivated methods to disentangle their structural components. In essence, treating the study of galaxies as a tomography-related inverse problem, where spatially resolved physical properties are inferred from projected and incomplete information, is key to understanding how galaxies form, evolve, and acquire their present-day structure.