Subhalo abundance matching and assembly bias in the EAGLE simulation

Understand

Subhalo abundance matching (SHAM) is a widely-used method to connect galaxies with dark matter structures in numerical simulations.

• SHAM predictions agree remarkably well with observations, yet they still lack strong theoretical support.
• We examine the performance, implementation, and assumptions of SHAM using the EAGLE project simulations.
• We find that $V_{\rm relax}$, the highest value of the circular velocity attained by a subhalo while it satisfies a relaxation criterion, is the subhalo property that correlates most strongly with galaxy stellar mass ($M_{\rm star}$).