Planetary nebula LOSVDs in six radial bins from the M 87 centre; the radial range is displayed above each panel. In each panel, the histogram limited by the black continuous line shows the LOSVD of the M 87 halo PNs as classified in Longobardi et al. (2015a). The histogram limited by the continuous red line shows the PN LOSVDs of the smooth M 87 halo once the ν_II ≃ 900 km s⁻¹ component is accounted for. For smooth M 87 halo PN LOSVDs we further plot two Gaussians, one with mean and dispersion computed as simple mean and standard deviation of the LOSV data (green continuous line), and another whose mean and dispersion value computed from the robust estimator (McNeil et al. 2010; Longobardi et al. 2015a, blue continuous line), and (2). The red shaded histogram shows the PN LOSVDs once the robust estimator is applied. We note that in the fourth and fifth radial bin the velocity dispersion estimates deviate the most because of the deviation of LOSVDs from a Gaussian and the limited statistics.