WoU-MMA: Aspects of Numerical Relativity and Relativistic Astrophysics

California Institute Of Technology, Pasadena CA

Investigators

Abstract

This award supports research in relativity and relativistic astrophysics, and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. Gravitational wave (GW) events of binary neutron star (NS) mergers are exciting sources for multi-messenger astronomy and astrophysics (MMA). With one such event (GW170817) already detected and several more anticipated over the next observing run of LIGO next year, one of the important questions of modern gravitational theory and MMA is to connect all the available channels of information to the underlying physics probed in the system. Specific questions include: What is the dense matter equation of state (EoS)? When and how are transients produced by merging NS? What is the general outcome of a NS-NS merger? Those can only be fully answered by novel insights from numerical relativity (NR) simulations of the merger and post-merger, which need to consider all the relevant (small-scale) microphysics associated with hot dense matter, magnetic fields, and weak-interaction physics. This award will make significant advances in the modeling of small-scale physics in NS-NS mergers. This project will also produce animations and movies of numerical simulations for public outreach. These will be made available to educators and the public via dedicated web pages, social media channels. In addition, graduate and undergraduate students supported by this project will receive extensive professional and educational training. This award will push the frontier in our understanding of the impact of realistic small-scale microphysics on the production of EM counterparts, relativistic outflow launching, and the outcome of NS-NS mergers. This will enable a novel class of NR simulations with significantly improved predictive power for the interpretation of GW events and their MMA aspects. Modeling small-scale dissipative effects (viscosities and heat conductivity) in relativistic fluids with magnetic fields in strong gravity, is also of fundamental interest to the gravitational, nuclear, and astrophysics communities. This project will develop a new cyberinfrastructure, a public simulation code for dissipative general-relativistic magnetohydrodynamics coupled with dynamic gravity, and study its applications to the post-merger stage of NS-NS coalescence. 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.