The evolution of the width of X‐ray flares with time in Gamma‐ray bursts

We present one of the most intriguing results obtained with an updated catalog of 113 early time (i.e. tpk≲1000 s) and 36 late time (i.e. tpk≳1000 s) X‐ray flares detected by Swift in the afterglows of Gamma‐Ray Bursts (GRB): the evolution of the width of the flares with time. This result, together with other properties investigated on early and late time flares and bright flares, provides a clear observational property that every model aiming at explaining the GRB emission has to face.