Session S4: Numerical Relativistic Astrophysics

Core-Collapse Supernova Mechanisms and their Signature in Gravitational Waves

Despite many decades of concerted theoretical effort and numerical modeling, the details of the core-collapse supernova explosion mechanism are still under debate. Indications are strong that the supernova mechanism is intrinsically multi-dimensional and involves (a combination of) postbounce energy deposition by neutrinos, convective instability, the standing-accretion-shock instability (SASI), unstable protoneutron star core g-mode oscillations, rotation, magneto-hydrodynamic effects, and nuclear burning. I review the current status of core-collapse supernova theory and modeling and introduce the ensemble of viable candidate explosion mechanisms that is emerging from recent multi-dimensional core collapse and postbounce supernova models. I go on to discuss gravitational-wave emission processes in core-collapse supernovae and present new results on the supernova gravitational-wave signature that were obtained with 2D/3D general relativistic and Newtonian simulations. I demonstrate how gravitational radiation from a core-collapse supernova observed by current and future detectors could be used to constrain the core-collapse supernova explosion mechanism.   

Interplaying analytical and numerical relativity in modeling binary black hole coalescences

The coalescence of two black holes is one of the most energetic events in the Universe, emitting 2-8\% of the initial rest-mass energy in gravitational waves. I will review how recent work at the interface between analytical and numerical relativity is improving our understanding of the binary black hole dynamics and gravitational-wave emission throughout inspiral, merger and ringdown phases. I will discuss the implications of those results in the search for gravitational-waves with ground and space based detectors, and in astrophysics, notably for the distribution of recoil velocities from merging black holes.   

Hydrodynamic Calculations of Compact Binary Mergers

I will briefly review recent results from relativistic hydrodynamic calculations of compact binary mergers, with particular emphasis on black hole - neutron star mergers. The general case with misaligned, spinning components leads to a rich variety of merger morphologies and outcomes, with a correspondingly broad variety of gravitational wave signatures.