Challenges in Computing Thermal and Non-thermal Emission from Relativistic Outflows

Multi-wavelength emission from relativistic outflows (e.g., jets and blast waves) provides us with valuable information about the physical conditions of the emitting plasma, its fluid dynamics and about the process which generates the outflows (i.e., the central engine). We use the relativistic hydrodynamics (RHD) code MRGENESIS coupled to a radiative transfer code SPEV to simulate the dynamics and emission of relativistic jets in two astrophysical scenarios, one involving non-thermal synchrotron emission in radio, and the other where thermal emission in optical is predominant. We give an overview of the structure of two codes and explain how they are coupled to compute the time-dependent emission from the evolving relativistic fluid. A considerable attention is given to the computational challenges that we face when applying SPEV to compute the light curves and spectra of relativistic jets.