Neutron Star Radii and Masses

Neutron stars offer the unique possibility of probing the equation of state of cold, ultradense matter. Understanding the properties of the neutron star interior is important for predicting the observational appearance of short gamma-ray bursts, the end stages of neutron star coalescence, and the outcomes of supernova explosions. I will present the recent measurements of neutron star radii and masses. I will show how the combination of the tightly constrained radii and the discovery of a 2 solar mass pulsar allows for the first astrophysical inference of the pressure of cold matter above nuclear saturation density. I will discuss the implications of this measurement for nuclear theory and astrophysics.