LCDM halo substructure properties revealed with high resolution and
  large volume cosmological simulations
  We investigate the structural properties, distribution and abundance of LCDM
dark matter subhaloes using the Phi-4096 and Uchuu suite of N-body cosmological
simulations. Thanks to the combination of their large volume, high mass
resolution and superb statistics, we are able to quantify -- for the first time
consistently over more than seven decades in ratio of subhalo-to-host-halo mass
-- dependencies of subhalo properties with mass, maximum circular velocity,
Vmax, host halo mass and distance to host halo centre. We also dissect the
evolution of these dependencies over cosmic time. We provide accurate fits for
the subhalo mass and velocity functions, both exhibiting decreasing power-law
slopes in the expected range of values and with no significant dependence on
redshift. We also find subhalo abundance to depend weakly on host halo mass. We
explore the distribution of subhaloes within their hosts and its evolution over
cosmic time for subhaloes located as deep as ~0.1 per cent of the host virial
radius. Subhalo structural properties are codified via a concentration
parameter, cV, that does not depend on any specific, pre-defined density
profile and relies only on Vmax. We derive the cV-Vmax relation in the range
7-1500 km/s and find an important dependence on distance of the subhalo to the
host halo centre, as already described in Molin\'e et al. (2017).
Interestingly, we also find subhaloes of the same mass to be significantly more
concentrated into more massive hosts. Finally, we investigate the redshift
evolution of cV, and provide accurate fits that take into account all mentioned
dependencies. Our results offer an unprecedented detailed characterization of
the subhalo population, consistent over a wide range of subhalo and host halo
masses, as well as cosmic times. Our work enables precision work in any future
research involving dark matter halo substructure.
