Constraining accreting millisecond X-ray pulsars by their pulse profiles

Neutron stars (NSs) provide unique astrophysical laboratories, with poorly understood ultradense matter present in their cores. By constraining their masses and radii, it is possible to put constraints on this regime of nuclear physics. For a few years, ‘pulse profile modeling’ has been able to provide such constraints with high time resolution spectral data from rotation powered millisecond pulsars from the Neutron Star Interior Composition Explorer (NICER). Accreting millisecond pulsars, being the progenitors of RMPs, are promising targets to tackle with this technique, potentially increasing the sample of neutron stars for which we have mass and radius constraints. We investigate constraining this class of pulsars using both synthetic and real NICER data. To achieve this we add an accretion disk and reflection line to the NS model and perform Bayesian parameter inference. We also discuss prospects of joint analysis with polarimetric X-ray data, which can provide helpful constraints on the geometry of the system.