Collapse to BH. Upper panel: the monotonically rising red curves represent the evolution of the central density with respect to the intial value ρ_c/ρ_c(t = 0) (as explained in the text the curves are truncated at the formation of the apparent horizon), while the monotonically decreasing blue curves represent the value of the lapse α at the origin. Solid lines indicate the spherically symmetric collapse and dashed lines the collapse of the rotating NS model D4. Bottom panel: the rising red curves represent the radius of the apparent horizon, while the decreasing blue curves are the ratio of the rest mass outside the apparent horizon with respect to the total rest mass. Again, solid lines indicate the spherically symmetric collapse and dashed lines the collapse of the rotating NS model D4. The vertical dotted line indicates the time t_AH when the apperent horizon forms.