XSEDE12

Science: A High throughput workflow environment for cosmological simulations

Abstract: The cause of cosmic acceleration remains an important unanswered question in cosmology. The Dark Energy Survey (DES) is a joint DoE-NSF project that will perform a sensitive survey of cosmic structure traced by galaxies and quasars across 5000 sq deg of sky. DES will be the first project to combine four different methods (supernova brightness, the acoustic scale of galaxy clustering, the population of groups and clusters of galaxies, and weak gravitational lensing) to study dark matter, dark energy, and departures from general relativistic gravity via evolution of the cosmic expansion rate and growth rate of linear density perturbations. Realizing the full statistical power of this and complementary surveys requires support from cosmological simulations to address the many potential sources of systematic error, particularly errors that are shared jointly across the tests of cosmic acceleration using cosmic structure. 

We are coordinating a Blind Cosmology Challenge (BCC) process for DES, in which a variety of synthetic sky realizations in different cosmologies will be analyzed, in a blind manner, by DES science teams. The BCC process requires us to generate a suite of roughly 50 2048^3-particle N-body simulations that sample the space-time structure in a range of cosmic volumes. These simulations are dressed with galaxies, and the resulting catalog-level truth tables are then processed with physical (e.g., gravitational lensing) and telescope/instrument effects (e.g., survey mask) before their release to science teams. We describe here our efforts to embed control of the catalog production process within a workflow engine that employs a service-oriented architecture to manage XSEDE job requests. We describe the approach, including workflow tests and extensions, and present first production results for the N-body portion of the workflow. We propose future extensions aimed toward a science gateway service for astronomical sky