ANALYZING X-RAY PULSAR PROFILES - ASYMMETRY AS A KEY TO GEOMETRY AND BEAM PATTERN

We describe a method for analyzing the pulse profiles of accreting X-r ay pulsars that is independent of a specific model and involves only a minimum of general assumptions on the system. The starting point is t he asymmetry observed in most pulse profiles and the assumption that i t is caused by a distorted magnetic dipole field. We find that it is p ossible to disentangle the contributions of the two emission regions f rom the pulse profile. Information on geometry and beam pattern can be extracted from these single-pole contributions. In some cases it is p ossible to determine the locations of the magnetic poles and reconstru ct the visible part of the beam pattern. The method is illustrated by two examples, a test case constructed from a model beam pattern and a pulse profile of Cen X-3.