Observed bend timescale versus the BH mass. The continuous line is the best-fitting following Eq. (4). The dashed lines illustrate the  ± 1 dex region around this model. Circles represent NLSy1s, squares represent Type-1 Seyferts, and the small green star is the Type-2 Seyfert. The open symbols are data-points reported in the literature and filled symbols are the data-points reported here. The Cygnus X-1 data are shown as a red big star. A dotted line is used to link multiple frequency bends for the same object.