Recipes for Baking Black Forest Databases: Building and Querying Black Hole Merger Trees from Cosmological Simulations

Large-scale N-body simulations play an important role in advancing our understanding of the formation and evolution of large structures in the universe. These computations require a large number of particles, in the order of 10-100 of billions, to realistically model phenomena such as the formation of galaxies. Among these particles, black holes play a dominant role on the formation of these structure. The properties of the black holes need to be assembled in merger tree histories to model the process where two or more black holes merge to form a larger one. In the past, these analyses have been carried out with custom approaches that no longer scale to the size of black hole datasets produced by current cosmological simulations. We present algorithms and strategies to store, in relational databases (RDBMS), a forest of black hole merger trees. We implemented this approach and present results with datasets containing 0.5 billion time series records belonging to over 2 million black holes. We demonstrate that this is a feasible approach to support interactive analysis and enables flexible exploration of black hole forest datasets.