  Dark matter (DM) can give observable effects decaying or annihilating with
production of electrons or/and photons. Such probability was widely researched
for our Galaxy. Here we consider one aspect of similar effect for Andromeda
galaxy. We explicitly estimate the energy of the photon of the medium
experiencing Inverse Compton (IC) scattering off electron in halo. These
photons can be registered by different experiments. Dark matter annihilation or
decay could be the source of high energy electrons in halo, though the source
could be of other origins too (e.g. running neutron stars). Because of
specifics in space orientation of Andromeda galaxy disk (a little inclined to
the line of sight), the difference in energies could arise for the photons from
two hemispheres of Andromeda halo. It is obtained that such asymmetry can be at
the level of several 10%.
