Mass and Spatial Distributions of Subhaloes in ΛCDM Cosmological Simulations

Subhalo populations surrounding massive dark matter haloes are studied by using three AMIGA simulations each having different mass resolutions. Our intention is to study mass and spatial distributions of dark matter subhaloes by using N-body simulations with broad scale of mass and spatial resolution. Also, massfraction distributions of subhaloes are calculated. Our analysis shows that the slope value -0.9 of the subhalo massfunction is in consistent with previous studies. However, subhalo massfunction is a function of redshift being the same for mainhalos within errorbars. In all simulations, massfraction between mainhalo and its subhaloes is between 0.1-0.2 and massfraction increases slightly with redshift and the mass of the mainhalo. Massfraction distribution of subhaloes is close to Gaussian distribution at z= 0, but differs at earlier epochs. Spatial distribution of subhaloes as measured in units of virial radius of the mainhalo is redshift independent and follows r^1/3 rule. Spatial distribution of haloes surrounding mainhaloes continues up to 3 times the virial radius with equal slope but lower amplitude. Beyond 10 times the virial radius, the mean distribution of haloes becomes uniform. We also found that if the subhalo content is analyzed, the minimum number of particles of the mainhaloes is 10⁴ and the number of particles in subhaloes should be at least 100.