Lorenzo Sironi is an Assistant Professor in the Department of Astronomy. He obtained his Ph.D. in 2011 in the Department of Astrophysical Sciences at Princeton University. Then, he moved to the Institute for Theory and Computation (ITC) at the Harvard-Smithsonian Center for Astrophysics, where he was first a NASA Einstein Post-Doctoral Fellow and then an ITC Post-Doctoral Fellow. His field of research is theoretical high-energy astrophysics. He investigates the origin of non-thermal emission from Pulsar Wind Nebulae (PWNe), AGN jets, gamma-ray bursts (GRBs), supernovae, galaxy clusters, and low-luminosity accretion flows like Sgr A* at the center of our Galaxy. It is still a mystery how these objects can accelerate particles up to the highly non-thermal energies required to explain the observed spectra, that typically extend from the radio up to the gamma-ray band. By means of ab initio large-scale plasma simulations, Prof. Sironi investigates particle acceleration in shocks and magnetic reconnection from first principles, with the aim of using the simulations to interpret the observations, and ultimately unveil the nature of astrophysical non-thermal sources.