Monday

The light curve of a kilonova following a neutron star merger contains a wealth of information that is complementary to that contained in the corresponding gravitational wave signal. In this talk I will present a rapid analytic framework for predicting kilonova light curves following neutron star (NS) mergers, where the main input parameters are binary-based properties measurable by GW detectors (chirp mass and mass ratio, orbital inclination) and properties dependent on the nuclear equation of state (tidal deformability, maximum NS mass). This enables synthesis of a kilonova sample for any NS source population, prediction of the light curve for a live kilonova given GW source parameters, or model fitting to an observed kilonova using GW constraints as priors.

I will then show the results of applying this code to GW170817. Using our framework and GW priors, we can uniquely trace the origin of each ejecta/luminosity component. Our results favour an additional luminosity source (in addition to lanthanide-poor dynamical ejecta) during the first day, well fit by a shock-heated cocoon model. The emission thereafter is dominated by a lanthanide-rich viscous wind. We place tight constraints on the mass ratio of the system, the maximum stable NS mass, and the radius of a 1.4 Msun NS.

Finally, I will demonstrate the utility of this code for informing future counterpart searches by applying it to the second NS merger detected by LIGO, GW190425.