Primordial black holes as dark matter candidates in the Galactic halo

Gravitational microlensing is a powerful method to constrain the abundance of massive dark objects in the Milky Way halo. We calculate the optical depth and the microlensing rate for events caused by Primordial Black Holes (PBHs) eventually distributed in the Milky Way halo, towards some selected directions of observation, as the Galactic bulge, the Large and the Small Magellanic Clouds and the M31 galaxy. The capability of the Euclid space telescope to constraint the abundance of PBHs with mass ≥ 10⁻⁷ M_⊙ in observation towards the Galactic bulge is also discussed.