Wolfgang Bangerth is a computational scientist and a professor of mathematics at Colorado State University. He is the founder and one of the current principal maintainers of the deal.II software library that provides everything you need to build finite element applications, including meshes, linear algebra functionality, a zoo of finite elements, and support from laptops to supercomputers with 100,000s of cores. With Timo Heister, he also started and is one of the current maintainers of the ASPECT code used to simulate convection in the Earth interior.
Timo Heister is an assistant professor in mathematical sciences at Clemson University in South Carolina. His research interests are in computational mathematics centered around the finite element method with focus on adaptive mesh refinement, parallel solvers, and applications to fluid dynamics and geophysics. He is one of the principal maintainers of the deal.II finite element library and involved in several other open source scientific software projects.