Michael Norman

University of California, San Diego

Astronomical Sciences

Blue Waters simulations suggest there are fewer faint galaxies than expected

There may be far fewer galaxies further out in the Universe than might be expected, suggests a new study based on simulations conducted using the Blue Waters supercomputer at the National Center for Supercomputing Applications, with resulting data transferred to SDSC Cloud at the San Diego Supercomputer Center at the University of California, San Diego, for future analysis. The study, published this week in the Astrophysical Journal Letters, shows the first results from the Renaissance Simulations, a suite of extremely high-resolution adaptive mesh refinement (AMR) calculations of high redshift galaxy formation. "Our work suggests that there are far fewer faint galaxies than one could previously infer," said principal investigator and lead author Brian W. O'Shea, an associate professor at Michigan State University with a joint appointment in the Department of Computational Mathematics, Science and Engineering; the Department of Physics and Astronomy; and the National Superconducting Cyclotron Laboratory..

Building blocks

Why do we care what happened 13 billion years ago?A bold lead question for an interview with an astrophysicist looking at the early universe, but one that doesn’t seem to faze Brian O’Shea. The Michigan State University professor just smiles across the Skype connection and then chuckles. ... O’Shea is no stranger to supercomputing or NCSA, dating back to his days as a student at the University of Illinois at Urbana-Champaign. As leader of a Petascale Computing Resource Allocations (PRAC) team that includes co-principal investigator Michael Norman and Hao Xu at the University of California, San Diego, John Wise of Georgia Tech, and Britton Smith of the University of Edinburgh, O’Shea’s been able to explore early galaxy formation and evolution. The team has published more than 16 papers, primarily in the Astrophysical Journal..

There May Be Nowhere Near the Number of Galaxies We Thought There Were

It looks like we might have overestimated how many neighbors we have. New predictions show that the universe might be an emptier place than we imagined. Since the Hubble launched, we’ve been seeing stunning image of the crowded universe. Most of the images come accompanied by assurances that what we see in the images is just the start. Astronomers have been excitedly guessing at the amount of faint, distant galaxies that they can’t see. Lurkers surely outnumbered visible galaxies. New simulations done on Blue Waters, a supercomputer at the National Center for Supercomputing Applications indicate that that isn’t the case..