GRB2 - The Afterglow and Long GRBs |
Speaker_ |
Amati, Lorenzo |
Talk _ |
The Ep,i-Eiso correlation and the nature of sub-energetic GRBs |
Abstract _ |
GRB 060218 is a peculiar event which shares several properties with GRB980425, the proto-type event of the GRB-SN connection: a very low redshift (0.0331), a very low isotropic-equivalent radiated energy, a clear association with a SN event (SN2006aj). However, while the Ep,i and Eiso values of GRB980425 are completely inconsistent with the Ep,i-Eiso (Amati) correlation holding for long GRBs/XRFs (as is possibly true for the other sub-energetic event GRB031203), those of GRB060218 are fully consistent with it. This evidence, togehter with the "achromatic" behaviour of the GRB060218 afterglow light curve and some properties of SN2006aj, challanges the popular explanations for the nature of sub-energetic GRBs (like, e.g., the very off-axis scenario) and points towards the existence of a (still mostly uncovered) population of intinsecally faint GRBs. |