Researchers are diving into the synthetic universe to help us better understand the real one. Using supercomputers at the US Department of Energy’s Argonne National Laboratory in Illinois, scientists created nearly 4 million simulated images of the universe as NASA’s Nancy Grace Roman Space Telescope and the Vera C. Rubin Observatory, jointly funded by the NSF (National Science Foundation ) and DOE in Chile will see it.
Michael Troxel, an associate professor of physics at Duke University in Durham, North Carolina, led the simulation campaign as part of a larger project called OpenUniverse. The team is now releasing a 10 terabyte subset of that data, with the remaining 390 terabytes to follow this fall as they are processed.
“Using Argonne’s now decommissioned Theta machine, we did in nine days what would take about 300 years on your laptop,” said Katrin Heitmann, a cosmologist and deputy director of Argonne’s High Energy Physics Division, who managed the supercomputer time project. “The results will shape Roman and Rubin’s future attempts to shed light on dark matter and dark energy, while also offering other scientists insight into the types of things they will be able to probe with data from the telescopes.”
Space dress rehearsal
For the first time, this simulation took into account the telescopes’ instrument performance, so it’s the most accurate view yet of the universe as Roman and Rubin will see it once they start observing. Rubin will begin operations in 2025 and NASA’s Roman will launch in May 2027.
The accuracy of the simulation is important because scientists will comb through the observatory’s future data in search of tiny elements that will help them unravel the biggest mysteries in cosmology.
Roman and Rubin will both investigate dark energy – a mysterious force believed to be accelerating the expansion of the universe. Because it plays a major role in running the universe, scientists are eager to learn more about it. Simulations like OpenUniverse are helping them understand the signatures each device imprints on the images, and they are now improving data processing methods to properly decipher future data. Then scientists will be able to make big discoveries even from weak signals.
“OpenUniverse allows us to calibrate our expectations of what we can discover with these telescopes,” said Jim Chiang, a scientist at DOE’s SLAC National Accelerator Laboratory in Menlo Park, California, who helped create the simulations. “It gives us a chance to apply our processing processes, better understand our analytics codes, and accurately interpret the results so we can be ready to use the real data as soon as it starts coming in.”
They will then continue using simulations to investigate physical and instrumental effects that could reproduce what observatories see in space.
Telescopic teamwork
It took a large and talented team from several organizations to run such a huge simulation.
“Few people in the world are skilled enough to run these simulations,” said Alina Kiessling, a scientist at NASA’s Jet Propulsion Laboratory (JPL) in Southern California and principal investigator of OpenUniverse. “This massive undertaking was only possible because of the collaboration between DOE, Argonne, SLAC and NASA, which brought together all the right resources and experts.”
And the project will continue to grow as Roman and Rubin begin to observe space.
“We will use the observations to make our simulations even more accurate,” Kiessling said. “This will give us a better view of the evolution of the universe over time and help us better understand the cosmology that ultimately shaped the universe.”
The Roman and Rubin simulations cover the same portion of the sky, a total of about 0.08 square degrees (roughly equivalent to a third of the sky area covered by the full Moon). The full simulation, to be released later this year, will cover 70 square degrees, roughly the area of ​​the sky covered by 350 full moons.
Their overlap allows scientists to learn to use the best aspects of each telescope—Rubin’s wider view and Roman’s sharper, deeper vision. The combination will yield better constraints than researchers could obtain from either observatory alone.
“Linking the simulations we’ve done allows us to make comparisons and see how Roman’s space probe will help improve the data from Rubin’s ground probe,” Heitmann said. “We can explore ways to break down the few objects that overlap in Rubin’s images and apply those corrections to his wider coverage.”
Scientists may consider modifying each telescope’s observing plans or data processing pipeline to benefit the combined use of both.
“We’ve made phenomenal progress in simplifying these pipelines and using them,” Kiessling said. Caltech/IPAC’s partnership with IRSA (Infrared Science Archive) makes simulated data available now, so that when researchers access real data in the future, they will already be familiar with these tools. “Now we want people to start working with simulations to see what improvements we can make and prepare to make the most efficient use of future data.”
OpenUniverse, along with other simulation tools developed by Roman’s Science Operations and Science Support centers, will prepare scientists for the large data sets expected from Roman. The project brings together dozens of experts from NASA JPL, DOE’s Argonne, IPAC and several US universities to coordinate with the Rome Project Infrastructure Teams, SLAC and the Rubin LSST DESC (Legacy Survey of Space and Time Dark Energy Science Collaboration). The Theta supercomputer was operated by the Argonne Leadership Computing Facility, a user facility of the DOE Office of Science.
The Nancy Grace Rome Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation from NASA’s Jet Propulsion Laboratory and Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team composed of scientists from various research institutions. Primary industry partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
The Vera C. Rubin Observatory is a federal project jointly funded by the National Science Foundation and the DOE Office of Science, with initial construction funding coming from private donations through the LSST Discovery Alliance.
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Author: Ashley Balzer
NASA Goddard Space Flight CenterGreenbelt, Md.
Media Contact:
Claire Andreoli
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NASA Goddard Space Flight Center, Greenbelt, Md.