SURFS: Riding the waves with Synthetic UniveRses For Surveys

الأصل · EN

We present the Synthetic UniveRses For Surveys (surfs) simulations, a set of N-body/Hydro simulations of the concordance Λ Cold Dark Matter () cosmology. These simulations use Planck cosmology, contain up to 10 billion particles and sample scales & halo masses down to 1 kpc & 10⁸ M. We identify and track haloes from z=24 to today using a state-of-the-art 6D halo finder and merger tree builder. We demonstrate that certain properties of halo merger trees are numerically converged for haloes composed of 100 particles. Haloes smoothly grow in mass, V max, with the mass history characterised by M(a)∝[-(a/β)α] where a is the scale factor, α(M)≈0.8 & β(M)≈0.024, with these parameters decreasing with decreasing halo mass. Subhaloes follow power-law cumulative mass and velocity functions, i.e. n(>f)∝ f⁻α with αₘ=0.83±0.01 and αV max=2.13±0.03 for mass & velocity respectively, independent of redshift, as seen in previous studies. The halo-to-halo scatter in amplitude is 0.9 dex. The number of subhaloes in a halo weakly correlates with a halo's concentration c & spin λ:haloes of high c & low λ have 60% more subhaloes than similar mass haloes of low c & high λ. High cadence tracking shows subhaloes are dynamic residents, with 25% leaving their host halo momentarily, becoming a backsplash subhalo, and another 20% changing hosts entirely, in agreement with previous studies. In general, subhaloes have elliptical orbits, e≈0.6, with periods of 2.3⁺².¹₋₁.₇ Gyrs. Subhaloes lose most of their mass at pericentric passage with mass loss rates of 40% Gyr⁻¹. These catalogues will be made publicly available.