Award-winning algorithm takes the search for habitable planets to a higher level

Here we see the Subaru telescope and other telescope installations at the top of Mauna Kea in Hawaii, United States. Image reproduced with the kind permission of Shutterstock.

An international team of scientists, including KAUST high-performance computing experts and astronomers from the Paris Observatory and Japan's National Observatory of Astronomy (NAOJ), in collaboration with NVIDIA, continues the search for habitable planets and the observation of the first galaxies of the time. level.

A demonstration of the sky was recently performed with the NAOJ's 8.2-meter Subaru Telescope and the Paris Observatory team is already upgrading the algorithms for future large telescopes. The KAUST Extreme Computing Research Center (ECRC) is collaborating with astronomers to develop advanced Extreme-AO algorithms that will address the formidable challenge of living exoplanet imaging.

"The imaging of exoplanets using large ground-based telescopes is very difficult because of the star-planet contrast and the blur induced by the Earth's atmosphere. Adaptive optics with very high performance, sometimes called "Extreme-AO", is essential, "said Dr. Hatem Ltaief, Senior Research Scientist at ECRC.

The collaboration has resulted in a radically new approach to OA: faster, larger, and much smarter control algorithms. Powered by the university's linear algebraic code running on NVIDIA graphics processing units (GPUs), the new computer system is constantly being optimized and even learning to anticipate rapidly changing optical perturbations induced by the Earth's atmosphere. .

The Subaru Telescope is located 14,000 feet above sea level, atop Mauna Kea in Hawaii, USA. Photo courtesy of the Subaru Telescope, Japan's National Astronomical Observatory.

"This fantastic new technology is already being used to take a closer look at exoplanets in orbit around nearby stars. With the largest telescopes currently being built by astronomers from 25 to 40 meters, new Earth-like planets orbiting nearby stars will be visualized and their atmospheric composition will be measured to look for signs of life such as l? oxygen, water and methane, "said Professor Damien Gratadour., astronomer at the Paris Observatory.

Researchers at ECRC have recently implemented a new singular value decomposition (SVD) algorithm, often referred to as the spearhead of digital linear algebra, to optimally control a small high-speed deformable mirror. to compensate for atmospheric turbulence. This research resulted in one of the best communication awards at the 2018 Advanced Computing Science Platform (PASC) conference in Basel, Switzerland. The innovation is already successfully used by astronomers to visualize exoplanets with the Subaru telescope located at 14 000 feet in Hawaii.

"This challenge is further exacerbated by large telescopes, where imagery of habitable planets in the Earth's atmosphere is notoriously difficult and requires a new approach to adaptive optics. Our previous AO systems were rather slow and lagging behind the rapidly changing optical aberration due to atmospheric turbulence, "said Professor Olivier Guyon, astronomer at the Subaru Telescope.

"The SVD algorithm developed by KAUST scientists allows us to correct in real-time the atmospheric blur of images taken by larger telescopes using the Extreme-AO more intelligently. The algorithm is now learning to optimize and we are no longer overwhelmed by turbulence, "he continued.

Astronomers are building a new generation of large telescopes offering about 15 times more light than today's largest telescopes. The giant Magellan telescope, the thirty-meter telescope and the very large telescope (shown here next to the university's flagship lighthouse) will be able to probe the biological activity of nearby exoplanets. Picture of Marta J. Golemiec.

Working closely with NVIDIA was critical to the success of the project.

"This is an unprecedented HPC challenge," said Steve Oberlin, director of technology for accelerated computing at NVIDIA. "The optical aberrations induced by the atmosphere change in milliseconds. On today's large telescopes, algorithms must calculate thousands of deformable actuator positions in one millisecond or less to make the images sharper. The Subaru Telescope is the highest land use recorded for this type of GPU systems. We continue to work with the team as the hardware is scaled to this exciting project due to the critical impact on NVIDIA GPU performance. "

The work of the project team adds to the historical contribution of the Middle East to the field of astronomy.

"We are helping astronomers make better use of today's and tomorrow's telescopes. It is interesting to note that many of the stars observed with the Subaru telescope were first sighted by star observers in the area and have retained their Arabic names. We hope to contribute to the tradition of astronomy in the region, "said Ltaief.

The University's HPC solutions also play a key role in designing future instruments for imaging the most distant galaxies. ECRC researchers, the Paris Observatory and NAOJ astronomers are now defining a common roadmap for software sustainability.