On the Galactic origin of ultra-high energy cosmic rays

It is shown that the acceleration of particles by a powerful relativistic jet associated with the activity of a supermassive black hole in the Galactic center several million years ago may explain the observed cosmic ray spectrum at energies higher than ${10}^{15}$ eV. The accelerated particles are efficiently confined in the extended magnetized gas halo created by the supernova and central black hole activity just after the Galaxy formation. We found that both the heavy and light chemical composition of ultra-high energy cosmic rays can be consistent with observations.