'Sinusoid' part of the analysis. The input light curve is iteratively pre-whitened, and the resulting parameters are non-linearly optimised. This step results in a mathematical model of the light curve in terms of a sum of sine waves and a linear trend for each sector (separately) and is applicable to any time series. In the second to last panel is the sum of sinusoids light curve model in orange and the bottom panel shows the residuals.