Modern Neutrino Physics in Simulations of Supernovae and Neutron Star Mergers

Dr. Sherwood Richers
Dr. Sherwood Richers

Abstract:  Neutrinos are thought to drive core-collapse supernova explosions and determine what elements get ejected from neutron star mergers, but they have a long history of causing problems for theoretical physics and astrophysics. Their weak coupling to matter usually leaves them out of equilibrium, requiring expensive numerical methods to understand how they transport energy and lepton number. Each neutrino is also born as a quantum mixture of mass states, which allows them to transform between flavors and makes them susceptible to violent flavor instabilities. However, the tools required to understand all of these effects are beginning to emerge. I will discuss new techniques for simulating neutrino transport and neutrino flavor transformation. Using these methods, I will demonstrate how numerical methods need to adapt to the dynamic environment of a neutron star merger, quantify how quickly collisions drive neutrinos to flavor states within a supernova, and show initial results of simulations of the fast flavor instability.

Speaker’s Bio : Sherwood's research interests are in simulations of high-energy astrophysical environments, including active galactic nuclei, core-collapse supernovae, and neutron star mergers.  Sherwood did his undergraduate work at the University of Virginia, his doctoral work at Caltech, and was a N3AS postdoctoral fellow at North Carolina State University and University of California- Berkeley (UC-Berkeley). He is now a NSF Astronomy and Astrophysics Postdoctoral Fellow at the UC- Berkeley, and his current primary interest is in understanding the role of neutrino flavor transformations in the core-collapse supernova explosion mechanism and nucleosynthesis in neutron star mergers.

Last Updated: October 19, 2020 - 11:55 am