Seminar GRBs associated with SNe: a highly correlated sample

Partecipanti: Maria Giovanna Dainotti (Università di Cracovia, Polonia e Stanford University, California)

ABSTRACT: The analysis of 176 GRB afterglow plateaus observed by Swift with known redshifts revealed that the subsample of long GRBs associated with SNe (GRB-SNe) present a very high correlation coefficient between luminosity at the end of the plateau phase LX(Ta) = LX and the end time of the plateau T_a ,(hereafter LT correlation).

Moreover, a category of GRBs with spectroscopically associated SNe show a particularly high degree of correlation, much higher than any other analyzed sample. Therefore, we conclude that there is a population of GRBs-SNe which shows very high LT correlation and a clearly associated supernova Ib/c is an indicator for this class.

These SNe Ib/c associated with GRBs obey also the peak-magnitude stretch relation, similar to that used to standardize the SNe Ia.

The fact that these two classes of GRB SNe have both a higher LT correlation and the peak-magnitude relation possibly suggests that the same physical mechanism could be responsible for both the relations. We also compare the LT correlation of GRBs with no associated SNe (long GRB-NO-SNe) at low redshift andthe GRB-SNe withspectroscopically associated SNe (the most correlated LT subsample), showing that these two populations have different LT trends thus possibly implying that the GRB-SNe possessing plateaus arecharacterized by a low luminosity nature compared to the long GRB-NO-SNe.