Frequency of Fragmentation artifact as a function of the events collected during the flaring period. The three panels are for the following temporal shapes: trapezoidal (left panel), triangular (central panel), temporal shape described in Eq. (9) (right panel). The clustering scheme of Eq. (2) is used. Continuous lines are used to connect the evaluated frequencies for the same tolerance parameter. Dashed lines are used to connect evaluated frequency to upper limits (99.87% c.l.). From top to bottom curves, tolerance parameters is set to 1, 3, 5, 10, 25, 50, 100.