Description
Neutron stars are the densest directly observable objects in the Universe with physical conditions that cannot be replicated byexperiments on Earth, thus serving as extremephysical laboratories. A major open question surrounding neutron stars aretheircorecomposition. The microphysics in the interior of a neutron star can be diagnosed viathe Equation of State (EOS)which is a relation between the macrophysical quantities of pressure and density. Many different EOS models have beenproposed butnone have been observationally confirmed to date. The EOS of a neutron star can beconstrained by precisestatistical measurements of its mass and radius, which can besimultaneously inferred using the novel technique of Pulse Profile Modelling(PPM) of X-ray spectral-timingevent data. PPM involves relativistic ray-tracing of the thermal X-ray emission originating from hot regions on the stellar surface. The Neutron Star Interior CompositionExplorer (NICER) space telescopewas launched with the purpose of acquiring datasuitable for PPM. In thistalk, I shall detail the PPM process, the NICER targets being analysed, highlight the current results and ongoing research, and the scope of future ofthe field.
