Correlation between the period and the redshift (left panel) as well as the correlation between the period and the supermassive black holes mass (right panel). In the left panel, the red dots represent the FSRQs and red triangles represent the BL Lacs. In the right panel the black dots represent the QPOs in AGNs, the red dots represent the QPOs in intermediate-mass BHs, and the blue dots represent the QPOs in BH X-ray binaries. The gray dash line is given in Abramowicz et al. (2004), the slope of which is −1, while the blue solid line with a slope of −1.27 is the linear fitting result of all points.