Observational data and corresponding fits taken from the literature. a) MXB 1659−29, data and fits from Cackett et al. (2008; 2013; open symbols). b) KS 1731−260, data and fits from Cackett et al. (2010a). c) EXO 0748−676, data and fits from Díaz Trigo et al. (2011) and Degenaar et al. (2011b). d) XTE J1701−462, data and fits from Fridriksson et al. (2011). Data with open symbols (XMM-3 and CXO-4) were not considered in fits. e) IGR J17480−2446, data and fits from Degenaar et al. (2013). Data from Chandra (circles), XMM-Newton (squares) and Swift (triangles) for all the sources. Exponential decay k_BT_s = a e^{− (t − t₀) /τ} + b (solid lines), and (broken) power-laws k_BT_s = α(t − t₀)^β (dashed lines) fits.