Cumulative gas mass versus cooling time for the objects in our sample for the mass vs. cooling time that is consistent with the pressure and entropy profiles reported in Eq. (5) and with the mass vs. entropy distribution for the isobaric model (Eq. (4)). For each object we plot the distributions for p = −2, −100, 1 (α = 0.5, 0.99, 2) and shade the region between them. The gas mass is normalized to the total gas mass. For comparison we show, as small filled circle following the same color coding of the gas mass distributions, the values of the cooling time obtained from a single temperature analysis of our spectra. The gray vertical box corresponds to t_cool = (3 − 3.3) 10⁹ Gyr. Note that only CC objects have mass distributions extending below this value.