Neutron Star Mass Distributions and the Equation of State of Dense Matter

We combine neutron star (NS) mass measurements with electromagnetic and gravitational wave observations to construct a comprehensive model which can describe the mass distributions of neutron stars in binaries and the dense matter equation of state (EoS). To understand how the mass distributions vary by populations, we assign different models to NS binaries depending on the companion stars: NS-NS or double neutron stars (DNS), NS - white dwarfs (NS-WD), and low-mass X-ray binaries (LMXB). In addition, we include two EoS models and study how different choices of the EoS impact the constraints on the NS mass-radius curve. Finally, we study how prior assumptions on the maximum mass create uncertainties in the observable matter at the high densities. Our current results show that NS masses in DNS, NS-WD, and LMXB have distinct probability densities with the peaks at 1.4 Μ_⊙, 1.6 Μ_⊙, and 1.7 Μ_⊙, respectively. We also observe that the softness of the EoS differs between our two EoS models and thus depends on the prior choice.