Free Fall onto Magnetized Neutron Stars

Abstract

Some compact X-ray sources show evidence of cyclotron line radiation from excited electron Landau orbits, powered by hydrogen and helium falling onto a neutron star atmosphere along the magnetic field. The slowing of the incident matter is discussed, including the spread in energy loss due to Coulomb scattering and direct nuclear reactions for disintegrating the QC particles-two problems which were first solved by Stuart Butler. The (X disintegrations, followed by neutron capture, lead to nuclear )I rays; the )I-ray intensity is (indirectly) coupled to the Coulomb energy loss and the cyclotron line emission.