Neutron star to neutrons, or ultra-dense quark-degenerate matter. Neutron stars are detected from their electromagnetic radiation. Neutron stars are usually observed to pulse radio waves and other electromagnetic radiation, and neutron stars observed with pulses are called pulsars. Pulsars' radiation is thought to be caused by particle acceleration near their magnetic poles, which need not be aligned with the rotational axis of the neutron star. It is thought that a large electrostatic field builds up near the magnetic poles, leading to electron emission. These electrons are magnetically accelerated along the field lines, leading to curvature radiation, with the radiation being strongly polarized
Neutron star towards the plane of curvature. In addition, high energy photons can interact with lower energy photons and the magnetic field for electron-positron pair production, which through electron–positron annihilation leads to further high energy photons. The radiation emanating from the magnetic poles of neutron stars can be described as "magnetospheric radiation", in reference to the magnetosphere of the neutron star. It is not to be confused with "magnetic dipole radiation", which is emitted because the magnetic axis is not aligned with the rotational axis, with a radiation frequency the same as the neutron star's rotational frequency. If the axis of rotation