An end-to-end test of neutron stars as particle accelerators

Combining resolved spectroscopy with deep imaging, XMM-Newton is providing new insights on the particle acceleration processes long known to be at work in the magnetospheres of isolated neutron stars. According to a standard theoretical interpretation, in neutron stars' magnetospheres particles are accelerated along the B field lines and, depending on their charge, they can either move outward, to propagate in space, or be funnelled back, towards the star surface. While particles impinging on the neutron star surface should heat it at well defined spots, outgoing ones could radiate extended features in the neutron star surroundings. By detecting hot spots, seen to come in and out of sight as the star rotates, as well as extended features trailing neutron stars as they move in the interstellar medium, XMMNewton provides the first end-to-end test to the particle acceleration process.