Nearly model-independent constraints on dense matter equation of state in a Bayesian approach

We apply a Bayesian approach to construct a large number of minimally constrained equations of state (EOSs) and study their correlations with a few selected properties of a neutron star (NS). Our set of minimal constraints includes a few basic properties of saturated nuclear matter and low-density pure neutron matter EOS which is obtained from a precise next-to-next-to-next-to-leading-order (N³LO) calculation in chiral effective field theory. The tidal deformability and radius of a NS with mass 1--2 M_ are found to be strongly correlated with the pressure of β-equilibrated matter at densities higher than the saturation density (ρ₀=0.16 fm^-3) in a nearly model-independent manner. These correlations are employed to parametrize the pressure for β-equilibrated matter, around 2ρ₀, as a function of neutron star mass and the corresponding tidal deformability. The maximum mass of the neutron star is also found to be strongly correlated with the pressure of β-equilibrated matter at densities ~4.5ρ₀.