  In many approaches to describe physics beyond the standard model, light
Nambu-Goldstone bosons (named axion-like particles or ALPS for their similarity
with the axion) are predicted to exist. For ALPs with a mass of neV,
photon-ALPs oscillation takes place in extra-galactic magnetic fields during
the propagation of very high energy gamma-ray photons leading to excess
radiation observed for optically thick sources. In order to verify this effect,
gamma-ray spectra from strong Galactic plane or non-galactic plane sources can
be used and the photon-ALPs mixing would lead to an energy dependent
suppression of the observed gamma-ray spectra. Here, we have used Fermi-LAT
observations of a sample of non Galactic plane gamma-ray pulsars located at
different line-of-sights to search for spectral signatures and compare the
result with the predictions using particular models for the Galactic magnetic
field.We find consistent evidence with our prevoius analysis of objects located
in the Galactic plane for a modulation of the spectra investigated at the level
of 3.66 standard deviations . In the framework of ALPS-photon oscillation, the
resulting parameters strongly depend upon the chosen magnetic field model, but
seem to be within reach of new experiments(e.g. IAXO).
