Einstein’s theory of general relativity describes all gravitational interactions in the universe, ranging from the force that pulls a falling apple to the Earth, to the expansion of the Universe itself. The equations of general relativity - called Einstein’s equations - are quite complicated and can be solved exactly, i.e. with pencil and paper, only under very special and unrealistic circumstances. Modeling more general scenarios requires computer simulations. Ongoing research efforts supported by this award aim at developing methods and approaches for such computer simulations, and to use these simulations to explore processes in relativistic astrophysics and general relativity. In the next few years this will include unresolved questions pertaining to the nature of general relativity — can arbitrarily small black holes form? — as well as effects of radiation in newly formed neutron stars and on black-hole accretion. Undergraduate students will participate in these activities, providing them with a “hands-on†research experience, and generating a research-enriched learning environment at Bowdoin College.
The scientific goals of these research efforts include the development and implementation of numerical algorithms for the solution of Einstein's equations of general relativity, as well as their application in the numerical modeling of relativistic objects, in particular neutron stars and black holes. In the next funding period these activities will focus on projects in two main areas, namely critical phenomena in the gravitational collapse to black holes, and dynamical effects of radiation. With regard to the former, the focus will be on situations in which the critical solution cannot be spherically symmetric. Building on experience and insights from previous work on critical collapse, these phenomena will be explored for the collapse of gravitational waves in vacuum spacetimes, an important problem that remains poorly understood even 25 years after it was first tackled. With regard to the latter, an approximate treatment of radiation transfer will be implemented and used to explore several scenarios in which radiation may play an important dynamical role. Examples include the evolution of supermassive stars up to the onset of radial instability, possible non-axisymmetric instabilities triggered by cooling in proto-neutron stars, and an exploration of super-Eddington flows in accretion onto black holes.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
