And now my share of the X-ray polarization pie. A very important source for me (did my Bachelor on it!) and for the IAAT: Her X-1. In the latest Nature Astronomy paper we use phase-resolved X-ray polarimetry to constrain the geometry of the pulsar.
We also add old optical polarimetry to the mix to show that the spin axis of the neutron star is misaligned with its orbital axis - a condition required to allow its free precession (suggested previously to explain observed changes of the pulse profile shape over the 35d super-orbital variability cycles). More observations are coming next year, and of course more observations of X-ray pulsars by IXPE too! The paper attracted quite a bit of attention, so we also have a press-release from the University and NASA