  We applied a decomposition method to the energy dependent pulse profiles of
the accreting binary pulsar A 0535+26, in order to identify the contribution of
the two magnetic poles of the neutron star and to obtain constraints on the
geometry of the system and on the beam pattern. We analyzed pulse profiles
obtained from RXTE observations in the X-ray regime. Basic assumptions of the
method are that the asymmetry observed in the pulse profiles is caused by
non-antipodal magnetic poles and that the emission regions have axisymmetric
beam patterns. Constraints on the geometry of the pulsar and a possible
solution of the beam pattern are given. We interpreted the reconstructed beam
pattern in terms of a geometrical model of a hollow column plus a halo of
scattered radiation on the neutron star surface, which includes relativistic
light deflection.
