The material falling in from the companion will hit a hard surface and this will shine in X-rays as an intense hot spot. When X-ray observatories, like NASA'ss RXTE observe these systems then the hot spot from the magnetic pole will flash as the neutron star rotates. The magnetic field on neutron stars can be as high as 1,000 billion times that on the earth. These are the strongest magnetic fields known anywhere in the universe, and X-ray astronomy is the only way to study them. A basic quest of science is to test the laws of physics under all conditions.
Unexpected discoveries can lead to break throughs in our understanding of the laws of nature.
An artists impression of the flow of material onto a neutron star. The material is funneled by the intense magnetic field onto the netron star pole. Not all neutron star systems have such intense magnetic fields, and it appears that in many of the low mass X-ray binary systems the field is much weaker. In these cases the flow of material onto the neutron star is more erratic, with the pulsations unstable. These oscillations seem to originate from the interaction of the neutron star with the surrounding accretion disk, or from instabilities in the captured material caused by the overwhelming intensity of the X-ray emission.