Mergers and Bulge Formation in Lambda-CDM: Which Mergers Matter?

Understand

We use a suite of semi-empirical models to predict galaxy merger rates and contributions to bulge growth as functions of merger mass, redshift, and mass ratio.

• The models use empirical halo occupation constraints to identify mergers, together with high-resolution simulations to quantify how mergers with different properties contribute to the bulge population.
• We find good agreement with a variety of observational constraints, and provide fitting functions for merger rates and contributions to bulge growth.
• We identify several robust conclusions.