Neutron star mergers in the era of gravitational wave astrophysics
Over the last few years, gravitational wave detectors have rapidly transformed from fundamental physics experiments to astrophysical observatories. The groundbreaking discovery of two merging black holes was followed by 10 more confirmed binary black hole mergers, 2 neutron star mergers, and dozens of additional events, which are still being analyzed. By combining gravitational wave and electromagnetic observations, theoretical models, and numerical simulations, we have been able to confirm the origin of short gamma-ray bursts, observe nucleosynthesis in action, test general relativity, and constrain the properties of dense nuclear matter. In this talk, I will review the physics of neutron star mergers, and discuss what we have learnt from recent observations. I will also provide an overview of the role of numerical simulations in the study of these systems, and of the most important challenges that these simulations face in their quest to model the gravitational wave and electromagnetic signals powered by merging neutron stars.