Fast Fourier transform of LCs from simulations. The top panels are for simulations of circular binaries, while the bottom panels are for simulations of eccentric e = 0.9 binaries. The left and right columns are for binaries with q = 1 and q = 0.1, respectively. The first row of each case shows the FFT of the Optical G band flux (blue line) and the FFT of the accretion rate (brown line) computed over 5-orbit windows within a total of 300/400 orbital periods at redshift z = 0.1,  0.4,  0.7. The second and the third rows show the FFT computed over 10- and 50-orbit windows, respectively.