Testing Subhalo Abundance Matching in Cosmological Smoothed Particle Hydrodynamics Simulations

Understand

Subhalo abundance matching (SHAM) is a technique for populating simulated dark matter distributions with galaxies, assuming a monotonic relation between a galaxy's stellar mass or luminosity and the mass of its parent dark matter halo or subhalo.

• We examine the accuracy of SHAM in two cosmological SPH simulations, one of which includes momentum-driven winds.
• The SPH simulations indeed show a nearly monotonic relation between stellar mass and halo mass provided that, for satellite galaxies, we use the mass of the subhalo at the epoch when it became a satellite.
• In each simulation, the median relation for central and satellite galaxies is nearly identical, though a somewhat larger fraction of satellites are outliers.