Top left: projected phase space, V_LOS vs. major axis distance (R), for all spectroscopically confirmed PNs (black asterisks) in the halo of M 87. Red lines separate the elliptical annuli analysed to isolate cold components associated to the substructure. Top-right: histograms of the LOSVD in the three elliptical annuli. In each panel, the blue lines show the best-fit model computed as a combination of three Gaussians. Black dashed lines show the relative contribution of each component to the LOSVD, with parameters for the cold components given in the plot. Bottom left: as in the top left panel, however, the green circles and magenta diamonds show the PNs associated with the cold secondary peaks in the LOSVD. Orange squares show a kinematically selected GC substructure from Romanowsky et al. (2012). Bottom right: probability that a PN is drawn from the halo component (dark grey area) or from the chevron (green, magenta areas). Stars represent PN probabilities at their measured V_LOS.