  The pulse profiles of the transient Be/X-ray binary EXO 2030+375 show strong
dependence on energy, as well as on its luminosity state, and are asymmetric in
shape. We want to identify the emission components of the two magnetic poles in
the pulsed emission to understand the geometry of the neutron star and its beam
pattern. We utilize a pulse-profile decomposition method that enables us to
find two symmetric pulse profiles from the magnetic poles of the neutron star.
The symmetry characteristics of these single-pole pulse profiles give
information about the position of the magnetic poles of the neutron star
relative to its rotation axis. We find a possible geometry for the neutron star
in EXO 2030+375 through the decomposition of the pulse profiles, which suggests
that one pole gets closer to the line of sight than the other and that, during
the revolution of the neutron star, both poles disappear behind the horizon for
a short period of time. A considerable fraction of the emission arises from a
halo while the pole is facing the observer and from the accretion stream of the
other pole while it is behind the neutron star, but the gravitational line
bending makes the emission visible to us.

High Energy Astrophysical Phenomena