Collapsar Disk Outflows: Nucleosynthesis and Multimessenger Signatures

Core collapse of a rapidly rotating massive star can lead to a "failed" supernova, forming a black hole surrounded by a neutrino-cooled accretion disk. These collapsar systems are natural laboratories for high-energy astrophysics, capable of powering long-duration gamma-ray burst jets and driving slower, energetic outflows that can unbind the progenitor star and produce an observable transient. In this talk, I will discuss how disk outflows shape the observable signatures of collapsars, drawing on recent global simulations that follow their evolution from core collapse through shock breakout and beyond. I will highlight their role in producing heavy elements, including the r-process, and in powering "engine-driven" supernovae. Finally, I will connect these models to multimessenger observables, focusing on the neutrino and gravitational wave signals expected from a Galactic event.

Bio: Rodrigo Fernandez is an Associate Professor in the Department of Physics at the University of Alberta. His research group studies neutron star mergers, supernovae, and other cosmic transients. These extraordinary events are responsible for the creation of most heavy elements in the Universe, and are the sites where stellar-mass black holes and neutron stars are born. Exploring these highly non-linear and complex systems involves investigating the interplay of multiple processes that, in some cases, operate in regimes beyond the reach of terrestrial laboratories. To unravel the secrets of these events, his group conducts large-scale numerical simulations using cutting-edge supercomputing facilities. The ultimate goal is to gain insight into these phenomena by generating predictions that can be tested with observations in photons, gravitational waves, and/or neutrinos, as well as nuclear astrophysics experiments. (Credit: https://sites.ualberta.ca/~rafernan/)