Neutron star merger ejecta estimation with kilonova light curve surrogates*

The observation of GW170817 sparked the era of multi-messenger astrophysics when a merger of two neutron stars was observed by both gravitational wave detection and its electromagnetic counterpart, the kilonova emission. Such neutron star mergers enrich the environment with neutron rich material. The mass and velocity of the ejecta material can be inferred independently from both the kilonova emission and the gravitational wave observation, however, those inferred from the kilonova AT2017gfo has been in tension with the properties inferred based on the gravitational wave signal GW170817. In this talk, we will present the newly developed surrogate models for light curves resulting from 2-D kilonova simulations (SuperNu) made for a large set of ejecta outflow morphologies and compositions. We use these models to then calculate the inferred ejecta properties, which helps identify the effect of morphologies and composition in this tension. We find that due to these additional ejecta models the tension is alleviated to some extent but there still remains significant disagreement. We will also show the capabilities of our surrogate models that can produce LCs for a range of ejecta component velocities, viewing angles, and at any broadband filter within a range of wavelengths.