Reconstructing the neutron-star equation of state from gravitational wave observations

Gravitational-wave observations of compact binaries containing neutron stars can be used to measure the neutron-star equation of state (EOS). The most reliable information is likely to come from measurements of the tidal deformability parameter lambda in binary neutron star systems, and previous work has shown that lambda can be measured with large errors by Advanced LIGO. In this talk, I will describe a method for stacking measurements of lambda from multiple inspiral events to reconstruct the EOS. We use Markov chain Monte Carlo simulations to estimate the parameters of a parameterized EOS that matches theoretical EOS models to a few percent. We find that, for realistic event rates, combining a year of gravitational-wave data with the constraints from causality and recent high mass neutron-star measurements, the EOS above nuclear density can be measured to better than a factor of two in most cases. We also find that the neutron-star radius can be measured to +/-1km. Current uncertainties in the post-Newtonian waveform model, however, lead to systematic errors in the EOS measurement that are as large as the statistical errors, and more accurate waveform models are needed to minimize this error.