Petascale Computing Unlocks Secrets of Gamma-ray Bursts 

This collapsing neutron star visualization is an example of astrophysical research enabled through high-performance computing.The PetaCactus project will advance such research in the area of gamma ray bursts.

Even with 21st-century cyberinfrastructure at their fingertips, today’s scientists still encounter problems so complex they require new computational methods and tools to solve. In astrophysics, one such problem is investigating and understanding gamma-ray bursts, thought to occur when a massive star collapses, creating a black hole. The resulting explosion sends bright flashes of gamma rays radiating across the universe.

Researchers working in relativistic astrophysics and computer science have developed high-performance computing software and algorithms that are currently being used to analyze other phenomena, such as the collisions of black holes or neutron stars. But, modeling gamma-ray bursts is a much more complex problem, involving many different physical processes that occur on different scales of space and time, and will require new advanced computational tools and physics models.

In a project they call “PetaCactus,” two Louisiana State University (LSU) professors, Gabrielle Allen and Erik Schnetter, have received National Science Foundation funding of more than $2 million in four different awards that will address these challenges in a comprehensive manner. Their research will develop the necessary physics applications, add them to Cactus and Carpet — existing, open-source software programs developed at LSU to support astrophysical research — and enable current and future high-performance computing systems to handle more complex science problems.

LSU Department of Computer Science Professor Allen and Department of Physics & Astronomy Research Professor Schnetter, who both have joint appointments with the LSU Center for Computation & Technology (CCT) lead the four grant proposals that make up the project, which they hope will ultimately lead to a method for studying gamma-ray bursts.

“In addition to the specific challenge of gamma-ray bursts, the codes, algorithms and software capabilities we will develop through this project will be used for other problems in science and engineering,” Allen said. “For example, the infrastructure we are creating could also be used to integrate together the diverse models needed to model the effects of hurricanes, where currently independent models are used for each component such as winds, storm surge or waves. This is just one example of the many areas where such technology could lead to breakthroughs and solutions for real-world problems.”

Allen and Schnetter plan to run their simulations on petascale computers, which are capable of running 1,000 trillion calculations per second and are the only class of machines becoming available that are large and fast enough to accurately model gamma-ray bursts. This particular research project will use the Blue Waters machine at the National Center for Supercomputing Applications in Urbana-Champaign, IL. The Blue Waters Consortium for Petascale Computing, of which LSU is a member, will deploy Blue Waters in early 2011 as the first dedicated petascale-class supercomputer for academic research.

“These awards each tackle a different part of the challenge,” Schnetter said. “Developing simulation codes for petascale computers is a major effort, and we need to develop new standards and tools that make it possible for the research communities in different locations to work together. We also need to be able to take advantage of new technologies, such as high-speed networks, to analyze the large data sets we will produce.”

The four grants contributing toward this overall research goal are:

• “PetaCactus: Unraveling the Supernova — Gamma-Ray Burst Mystery.”  This award, funded at $1.4 million for five years and led by Schnetter, also involves researchers at Caltech and Princeton, and will develop the fundamental physics models and algorithms needed for codes to analyze gamma-ray bursts.

• “Collaborative Research:  Community Infrastructure for General Relativistic MHD,” or CIGR, led by Allen, is a $1 million collaborative project involving partners Rochester Institute of Technology and Georgia Tech. This award will provide the community infrastructure and open code base — based on Cactus and Carpet — that will the support multi-physics simulations needed for modern relativistic astrophysics.

• “Enabling Science at the Petascale: From Binary Systems and Stellar Core Collapse To Gamma-Ray Bursts,” led by Schnetter and funded at $35,896 for three years, will allow the LSU research team to work with the Blue Waters staff at the National Center for Supercomputing Applications to prepare for the new petascale facility.

• “Strategies for Remote Visualization on a Dynamically Configurable Testbed” is led by Allen. This part of the project is funded at nearly $300,000 for two years, and funds a research team in applications of high-speed networks to prototype interactive visualization tools to produce images of gamma-ray bursts from the research data created on the petascale computer.

“This groundbreaking project is a good example of how CCT provides a forum for interdisciplinary research teams to work together,” said CCT Interim Director Stephen David Beck. “In order to study complex problems like gamma ray bursts, it is important to create an environment where physicists and computer scientists can collaborate, and we are pleased CCT supports this kind of joint research. I am very excited for Professor Allen and Professor Schnetter, and their entire research team, for initiating this new and innovative work.”