  A recent article from the Pierre Auger Collaboration links the direction of
charged cosmic rays to possible extragalactic sites of emission. The
correlation of the direction of such particles with the direction of the
emitter allows constraining the value of large-scale magnetic fields B.
Assuming for B a coherence length in the range between 1 Mpc and 10 Mpc, we
find values of B between 0.3 and 0.9 nG.
