Speaker
Description
The paradigmatic understanding of the physical processes operating in the relativistic jets of blazars, traditionally framed within one-zone models, has been challenged by recent observational evidence. IXPE multi-wavelength campaigns support multi-zone scenarios; delays between radio and gamma-ray flares point to jet acceleration and propagation effects; and short- and long-term inter-band variability reveal a complex interplay between particle acceleration and radiative cooling. These findings also indicate a strong connection between the dissipation site and the balance between cooling and acceleration channels.
Despite this substantial body of phenomenological evidence, theoretical interpretation and modeling still face major challenges, largely due to parameter degeneracies and the limited discriminatory power of current models. As a result, a clear understanding of the connection between micro- and macro-physical processes remains elusive. In this talk, I will discuss key phenomenological patterns emerging from recent observations and show how they can be used to develop modeling frameworks that connect microphysical acceleration processes with the large-scale jet phenomenology observed in blazars. Particular attention will be devoted to the acceleration process, comparing scenarios in which shocks act as the main sites of particle acceleration with alternatives based on hierarchical turbulence and magnetic reconnection, while emphasizing the ubiquitous role of a stochastic acceleration component.