Searching double-peaked emission line profiles in the spectra of galaxies through the symmetry of the cross-correlation function

The presence of double-peaked/multicomponent emission line profiles in spectra of galaxies is commonly done by visual inspection. However, the identification of complex emission line profiles by eye is unapproachable for large databases such as the Sloan Digital Sky Survey (SDSS) or the integral field spectroscopy surveys of galaxies (e.g. CALIFA or MaNGA). We describe a quick method involving the cross-correlation technique for detecting the presence of complex (double-peaked or multiple components) profiles in the spectra of galaxies, deriving simultaneously a first estimation of the velocity dispersions and radial velocities of the dominant gaseous component. We illustrate the proposed procedure with the well-known complex [OIII]4959,5007 profiles of the central region of NGC1068.