The outer regions of the giant Virgo galaxy M87. Kinematic separation of stellar halo and intracluster light

Understand

We present a spectroscopic study of 287 Planetary Nebulas (PNs) in a total area of ~0.4 deg^2 around the BCG M87 in Virgo A.

• With these data we can distinguish the stellar halo from the co-spatial intracluster light (ICL).
• PNs were identified from their narrow and symmetric redshifted lambda 5007\4959 Angstrom [OIII] emission lines, and the absence of significant continuum.
• We implement a robust technique to measure the halo velocity dispersion from the projected phase-space to identify PNs associated with the M87 halo and ICL.