Breaking the symmetry: X-ray polarization from a spreading layer on a tilted weakly magnetized neutron star

When modeling the emission from an X-ray binary system, we often assume that the rotational axis of the compact object is aligned with that of the binary system. While often considered irrelevant for spectroscopic observations, the orientation of the binary system is crucial for polarimetric properties. With the recent advent of X-ray polarimetric observations enabled by the ( Imaging X-ray Polarimetry Explorer indications of a possible misalignment of the neutron star's rotational axis with respect to the binary axis have been reported. Following these indications, we present an analytical model for the polarimetric properties of emission arising from a spreading layer on an inclined weakly magnetized neutron star (WMNS). We discuss the expected polarimetric properties and study the impact of the geometrical parameters of the system on the polarization of WMNS emission. We compare our results with those for aligned systems. Finally, we discuss applications of the model to recent and upcoming X-ray polarimetric observations with and mention the suggestions for further development of the model.