Accretion by magnetic neutron stars

Most of the bright, periodically pulsing X‐ray sources in the Galaxy are strongly magnetic, rotating neutron stars accreting matter from a binary companion. Some X‐ray and γ‐ray burst sources may also be strongly magnetic neutron stars accreting matter from a binary companion or the interstellar medium. In such systems the magnetic field of the neutron star creates a magnetosphere about the star. This review first describes the qualitative features that are characteristic of all flows onto strongly magnetic neutron stars and then discusses accretion from a thin disk and spherically symmmetric radial accretion in more detail, with emphasis on the scale and structure of the magnetosphere. Work on plasma flow inside the magnetosphere and the physics of accretion torques is described. Finally, some interesting unsolved problems in neutron star magnetospheric physics are indicated.