Upper: Fourier Transform (amplitude) of the Galaxy spectrum. Middle: FT of the star spectrum (note the higher frequencies because of the sharper absorption lines). Lower: the ratio of the Galaxy and Star FTs. This should be a Gaussian, since it is the FT of the broadening function. A Gaussian is fitted (within the bar range) and this fit yields the stellar velocity dispersion. (The redshift is obtained from the phases of the fourier transform).