The halo mass function through the cosmic ages

In this paper, we investigate how the dark matter halo mass function evolves with redshift, based on a suite of very large (with N p = 3072 3 -6000 3 particles) cosmological N-body simulations. Our halo catalogue data span a redshift range of z = 0-30, allowing us to probe the mass function from the Dark Ages to the present. We utilize both the friends-of-friends (FOF) and spherical overdensity (SO) halo-finding methods to directly compare the mass function derived using these commonly used halo definitions. The mass function from SO haloes exhibits a clear evolution with redshift, especially during the recent era of dark energy dominance (z 20, the SO algorithm finds a 50-80 per cent lower collapsed fraction in high-mass haloes than the FOF algorithm.