Centre for Radiophysics and Space Research, Department of Astronomy, Cornell University, Ithaca, NY 14853, USA;Ioffe Physico-Technical Institute, Politekhnicheskaya 26, 194021 Saint-Petersburg, Russia
Abstract:
Recent observations of thermally emitting isolated neutron stars revealed spectral features that could be interpreted as radiative transitions of He in a magnetized neutron star atmosphere. We present Hartree–Fock calculations of the polarization-dependent photoionization cross-sections of the He atom in strong magnetic fields ranging from 1012 to 1014 G. Convenient fitting formulae for the cross-sections are given along with the related oscillator strengths for various bound–bound transitions. The effects of finite nucleus mass on the radiative absorption cross-sections are examined using perturbation theory.