  The supernova SN 2006aj associated with GRB 060218 is the second-closest
GRB-SN observed to date ($z$=0.033) and is the clearest example of a SN
associated with a Swift GRB with the earliest optical spectroscopy. Its optical
data showed that this is the fastest evolving and among the least luminous
GRB-SNe (70% as luminous as SN1998bw). However, its expansion velocity and a
comparison with other stripped-envelope SNe suggest that SN2006aj is an
intermediate object between Type Ic GRB-SNe and those not accompained by a GRB.
High-resolution optical spectroscopy together with SDSS pre-burst observations
revealed that the host galaxy of SN2006aj is a low-luminosity, metal-poor
star-forming dwarf galaxy.
