Swift GRBs and the Ep,i-Eiso correlation

The E-p,E-i-E-iso correlation is one of the most intriguing and debated observational evidences in Gamma-Ray Bursts (GRB) astrophysics. Swift, with its high sensitivity and fast pointing capabilities, is reducing a lot the impact of selection effects in the sample of GRBs with known redshift (and thus E-p,E-i and E-iso). Moreover, in several cases it allows the detection of the soft tail of the prompt emission, and thus a more accurate estimate of Er,i with respect to previous satellites. I present and discuss the location in the E-p,E-i-E-iso plane of Swift GRBs with known redshift and estimated Ep,i, showing that all long events (including peculiar events like GRB 060218 and GRB 060614) are consistent with the E,i-Eiso correlation. In contrast, short GRBs are not consistent with it, an evidence further supporting the hypothesis of different emission mechanisms at work in the two classes of GRBs. I also show, and briefly discuss, the intriguing evidence that the soft tail of the short GRB 050724 is consistent with the correlation.