Interpreting the multi-messenger picture of colliding neutron stars

Neutron stars are among the densest objects in the Universe, and the collision of two neutron stars ranks as one of the most energetic events known. The groundbreaking multimessenger detection of gravitational waves and electromagnetic signals from such a collision marked a revolution in astronomy, yielding profound insights into fundamental physics. Accurate interpretation of binary neutron star mergers hinges on robust models of the final stages of their coalescence. In this talk, we demonstrate how numerical-relativity simulations can be utilized to develop these theoretical models, capturing both gravitational-wave and electromagnetic signatures. By integrating these models with nuclear physics computations and experimental data, we can measure the equation of state of neutron stars, elucidate the production of heavy elements, and impose new constraints on the Hubble constant.