Implications of the consistency of GRB 060218 / SN 2006 aj with the E p , i – E iso correlation

The gamma-ray burst GRB 060218 is an important event because of its very low redshift z = 0.0331, its low isotropic–equivalent radiated energy E iso ∼ 7 × 10 49 erg and its clear association with a supernova (SN) event (SN 2006aj). Under these respects, GRB 060218 is the event most similar to GRB 980425, the proto–type event of the GRB–SN connection. However, while the peak energy E p,i and E iso values of GRB 980425 are inconsistent with the E p,i – E iso (Amati) correlation holding for long GRBs/XRFs, GRB 060218 is fully consistent with it. One of the popular explanations of the inconsistency of GRB 980425 with the E p,i – E iso correlation is that it was a 'normal' GRBs seen off-axis. Our result implies that this is not the case for GRB 060218. This is also confirmed by the 'chromatic' behavior of the afterglow light curves measured by Swift. In this Letter we discuss some implications of our finding on the present understanding of the GRB/SN connection.