Poster Presentation Astronomical Society of Australia Annual Scientific Meeting including HWWS 2013

Mass assembly history of main sequence galaxy halos. (#214)

Camila Correa 1 , Alan Duffy 1 , Stuart Wyithe 1
  1. University of Melbourne, Parkville, VIC, Australia

We use cosmological hydrodynamical simulations from OWLS project to build halo merger trees and study the mass assembly history of main sequence galaxy halos. We propose a simple 1-parameter formula for the mass assembly history (MAH) of halos as a function of redshift. We find that it simultaneously presents a close fit to the mean total mass trajectories of halos and its time derivative provides an accurate estimate of the total accretion rate. We make detailed comparisons of analytically derived accretion rates, as well as MAHs derived from other N-body simulations, and find excellent agreement (with one exception of an often used scheme). We show that by using the present day halo mass (M0) as a unique parameter in our model, we can easily determine the halo mass and accretion rate at earlier epochs .