Toward Binary Neutron Star GR(M)HD Simulations with superGRoovy

Binary–neutron–star (BNS) mergers are multimessenger probes of dense matter and strong-field gravity, driving the need for robust, scalable general-relativistic (magneto)hydrodynamics (GR(M)HD) simulations. We present the integration of the superGRoovy framework---which couples the GRHayL-based GRoovy GR(M)HD solver to the highly scalable, Charm++-based superB/NRPy infrastructure---for BNS applications employing advanced, tabulated, finite-temperature equations of state. While expensive, fisheye grids are extremely scalable and avoid mesh refinement interfaces, mitigating errors induced at grid boundaries and reducing synchronization overhead. We will present verification tests, scaling measurements, and progress toward BNS simulations. This single-grid fisheye strategy is a waypoint toward highly efficient multicoordinate, multipatch infrastructures provided by BlackHoles@Home and toward increased physical realism with more advanced neutrino physics handling.