Reconciling Observations of the Galaxy Merger Rate
Jennifer Lotz (NOAO)
One of the most important tests of Lambda-CDM cosmology on galaxy scales is the hierarchical nature of galaxy assembly. If small proto-galaxies collapse first from over-densities in the primordial universe, then they must grow with time through discrete mergers and accretion. However, observational constraints on the galaxy merger rate and its evolution with redshift remain highly uncertain. A key obstacle to measuring the galaxy merger rate has been the unknown timescales for identifying on-going mergers. I will present the first realistic constraints on the merger observability timescales from a large suite of galaxy merger simulations. Using the timescales from our simulations, I attempt to reconcile estimates of the galaxy merger rate. I will also discuss the implications for gas-poor and minor mergers.
Contact: Francois Schweizer
Jennifer Lotz (NOAO)
One of the most important tests of Lambda-CDM cosmology on galaxy scales is the hierarchical nature of galaxy assembly. If small proto-galaxies collapse first from over-densities in the primordial universe, then they must grow with time through discrete mergers and accretion. However, observational constraints on the galaxy merger rate and its evolution with redshift remain highly uncertain. A key obstacle to measuring the galaxy merger rate has been the unknown timescales for identifying on-going mergers. I will present the first realistic constraints on the merger observability timescales from a large suite of galaxy merger simulations. Using the timescales from our simulations, I attempt to reconcile estimates of the galaxy merger rate. I will also discuss the implications for gas-poor and minor mergers.
Contact: Francois Schweizer
