  We observe solitonic vortices in an atomic Bose-Einstein condensate after
free expansion. Clear signatures of the nature of such defects are the twisted
planar density depletion around the vortex line, observed in absorption images,
and the double dislocation in the interference pattern obtained through
homodyne techniques. Both methods allow us to determine the sign of the
quantized circulation. Experimental observations agree with numerical
simulations. These solitonic vortices are the decay product of phase defects of
the BEC order parameter spontaneously created after a rapid quench across the
BEC transition in a cigar-shaped harmonic trap and are shown to have a very
long lifetime.
