Kilonova simulations: connecting observations with the underlying physics

Kilonova observations contain information about heavy-element r-process nucleosynthesis and the behaviour of high-density matter. However, interpreting what these observations tell us about the underlying physics requires detailed modelling. We outline recent kilonova radiative transfer simulations that are based on hydrodynamical models of neutron star merger ejecta. The simulated spectra in the polar directions show a remarkably similar evolution to the observations of AT2017gfo. Using these simulations, we show the importance of accurate atomic data for kilonova modelling, as well as the importance of three-dimensional simulations. By improving radiative transfer simulations and by extending this study to consider a range of theoretical equations of state, simulations will be able to connect observations to the underlying merger physics and place constraints on the high-density equation of state and r-process nucleosynthesis.This article is part of the Theo Murphy meeting issue 'Multi-messenger gravitational lensing (Part 2)'.