Penticton, BC: Canadian astrophysicists have run the world's largest gas particle cosmology simulation on the SHARCNET supercomputer at McMaster University. The 270 million particle hydrodynamical simulation of galaxy clusters in a cosmological volume is being presented by Dr. James Wadsley at the Canadian Astronomical Society's annual meeting in Penticton, BC. This work is of particular interest because it demonstrates that Canada is competing at the international forefront in computational astrophysics.

Dr. James Wadsley and Dr. Hugh Couchman of McMaster University created a realisation of a cubic portion of the universe 1.3 Billion light years across using 135 million gas and 135 million dark matter particles. This volume models structures larger than the APM Survey's "Great Wall" of galaxies and resolves down to galaxy clusters and large galaxies. The simulation was run using the parallel computer program "Gasoline" on 88 processors of the McMaster supercomputer "Idra", taking 50 days to complete, the equivalent of 11 years processing on a single computer. Idra is the 112 processor Compaq supercomputer cluster at McMaster purchased as part of the SHARCNET project and is listed in the world-wide top 500 supercomputer list. SHARCNET ( is a project to develop a network of high-performance computing clusters in SW Ontario funded by the Ontario Research and Development Challenge Fund and the Canada Foundation for Innovation. Gasoline was developed by Dr. Wadsley, Dr. Joachim Stadel (Victoria) and Dr. Tom Quinn (U. Washington).

Working with Marcelo Ruetalo, Dr. Dick Bond and Dr. Carlo Contaldi of the Canadian Institute for Theoretical Astrophysics, the authors are using hydrodynamical simulations to predict distortions in the primordial Cosmic Microwave Background due to the hot gas in massive galaxy clusters, the Sunyaev-Zel'dovich effect. Preliminary results indicate that the effect is consistent with the new high resolution observations taken by Caltech's Cosmic Background Imager experiment. The homogenous and versatile simulated dataset also provides precise estimates of the clustering of galaxy clusters, of shear due to weak gravitational lensing and a sample of over 1000 X-ray clusters. This research is supported by SHARCNET, grants from the National Science and Engineering Research Council of Canada and the Canadian Institute for Advanced Research.

Images and movies of the simulation are available at:

For more information contact:

Dr. James Wadsley
McMaster University
Phone: (905) 525 9140 x 27663

Dr. Hugh Couchman
McMaster University
Phone: (905) 525 9140 x 27860