Tracing galactic accelerators

Cosmic rays are a dynamically important component of our Galaxy, yet their sources and propagation through the Galaxy remain incompletely understood. Because charged cosmic rays are deflected by Galactic magnetic fields, gamma rays and neutrinos provide essential complementary probes of their origin and transport.
This thesis investigates cosmic-ray transport and Galactic particle accelerators using
high-energy gamma-ray and neutrino observations. First, time-dependent models of particle transport around evolved pulsar wind nebulae are developed and applied to the Geminga and Monogem TeV halos, incorporating particle injection, radiative losses, pulsar proper motion, and spatially varying diffusion. The gamma-ray, synchrotron, and local positron emission predicted by these models is compared with existing observations. The evolved pulsar wind nebula HESS J1857+026 is studied as an additional system of near-source diffusion.
The prospects of the Cherenkov Telescope Array Observatory (CTAO) for constraining TeV-halo properties are then investigated using forward-folded mock observations and likelihood analyses. These studies examine halo detectability, transport parameters, the complementarity of CTAO-North and CTAO-South, and the effects of astrophysical backgrounds.
Finally, the thesis extends from individual leptonic sources to population-level hadronic emission. A simulation-based inference framework is developed to investigate whether Galactic neutrino observations can distinguish diffuse emission from the collective contribution of an unresolved population of cosmic-ray accelerators.