Panel a) optimal BLS spectrum of Kepler’s KOI 1574 (blue) and its BLS_ternd (red) after removing planet candidate KOI 1574.01 using all available data through Quarter 13. Panel b) same, after removing BLS_ternd. Panels c), d) two zoomed-in regions with significant local peaks. Optimal frequency sampling is evident by the fact that each peak is sampled with similar number of samples despite the large difference in width.