LombScargle GLS
The Generalized LombScargle (GLS) periodogram was introduced by Zechmeister & Kürster1 in 2009. Compared to the 'classical' LombScargle periodogram, the GLS takes into account measurement (brightness) errors and a constant term in the fit of the wave function. As a result, GLS provides more accurate frequencies, is less susceptible to aliasing, and gives a much better determination of the spectral intensity. Peranso furthermore calculates and shows three False Alarm Probability (FAP) levels to help distinguish between significant and spurious peaks. We compute FAP levels of 10%, 5%, and 1%, which are visually represented in the Period Window by resp. an orange, green and red colored dashed horizontal line. The computation of these FAP levels is different from the standard FAP method supported by Peranso, which uses a Monte Carlo Permutation Procedure in order to determine FAP levels. This is much more timeconsuming than the actual FAP computations through the GLS. The LombScargle GLS dialog box is similar to the LombScargle dialog box. Prominent periods of the Period Window appear as peaks. Generalized LombScargle (GLS) False Alarm Probability (1) M. Zechmeister & M. Kürster, The generalised LombScargle periodogram. A New formalism for the floatingmean and Keplerian periodograms, 2009, A&A, 496, 577 
