Physical Sciences and Mathematics Commons^™

Galaxy Merger Statistics And Inferred Bulge-To-Disk Ratios In Cosmological Sph Simulations, Ah Maller, N Katz, D Keres, R Dave, Dh Weinberg

Astronomy Department Faculty Publication Series

We construct merger trees for galaxies identified in a cosmological hydrodynamic simulation and use them to characterize predicted merger rates as a function of redshift, galaxy mass, and merger mass ratio. At z = 0.3, we find a mean rate of 0.054 mergers per galaxy per Gyr above a 1 : 2 mass ratio threshold for massive galaxies (baryonic mass above 6.4 × 10¹⁰ M), but only 0.018 Gyr^-1 for lower mass galaxies. The mass ratio distribution is R for the massive galaxy sample, so high-mass mergers dominate the total merger growth rate. The predicted rates increase …