Constraining the Neutron Star Equation of State with NICER

One of the principal goals of the Neutron Star Interior Composition Explorer (NICER) is to carry out sensitive X-ray observations of neutron stars in order to constrain the poorly understood equation of state of cold matter at densities exceeding the nuclear saturation density. The NICER mission is focusing on measuring the masses and radii of several relatively bright, thermally-emitting, rotation-powered millisecond pulsars, by fitting sophisticated models that incorporate all relevant relativistic effects and atmospheric radiation transfer processes to their periodic soft X-ray modulations. We will present NICER data of the targets observed for this purpose, the technique and models that have been developed by the NICER team, and the first set of results.