Researchers delve into a synthetic universe to help us better understand the real universe. Using supercomputers at the Department of Energy’s Argonne National Laboratory in Illinois, scientists have created nearly 4 million simulated images of the cosmos from NASA’s Nancy Grace Roman Space Telescope and the Vera C. Rubin Observatory, jointly funded by NSF (the 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 broader project called OpenUniverse. The team is now releasing a subset of 10 terabytes of this data, with the remaining 390 terabytes to follow once processed this fall.
“Using Argonne’s now retired Theta machine, we accomplished in about nine days what would have taken about 300 years on a laptop,” said Katrin Heitmann, a cosmologist and deputy director of Argonne’s High Energy Physics Department, who managed the project’s supercomputing time. “The results will shape Roman and Rubin’s future efforts to illuminate dark matter and dark energy, while giving other scientists a taste of the types of things they can investigate using data from the telescopes.”
A cosmic dress rehearsal
For the first time, this simulation takes the instrument performance of the telescopes into account, making it the most accurate preview yet of the cosmos as Roman and Rubin will see it once they begin observing. Rubin will become operational in 2025 and NASA’s Roman will launch in May 2027.
The accuracy of the simulation is important because scientists will sift through future data from the observatories looking for small features that will help them unravel the biggest mysteries in cosmology.
Roman and Rubin will both investigate dark energy – the mysterious force believed to be accelerating the expansion of the universe. Because it plays an important role in governing the cosmos, scientists are eager to learn more about it. Simulations like OpenUniverse help them understand the signatures each instrument imprints on the images and smooth out the data processing methods now so they can correctly decipher future data. Then scientists will be able to make major discoveries even on the basis of weak signals.
“OpenUniverse lets us calibrate our expectations of what we can discover with these telescopes,” said Jim Chiang, a staff scientist at DOE’s SLAC National Accelerator Laboratory in Menlo Park, California, who helped create the simulations. “It gives us a chance to practice our processing pipelines, better understand our analysis codes, and accurately interpret the results so we can prepare to use the real data as soon as it comes in.”
Then they will continue to use simulations to investigate the physics and instrument effects that could reproduce what the observatories see in the universe.
Telescopic teamwork
It took a large and talented team from different organizations to run such an immense simulation.
“There are few people in the world skilled enough to run these simulations,” said Alina Kiessling, a research 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 the DOE, Argonne, SLAC and NASA, which brought together all the right resources and experts.”
And the project will ramp up even further once Roman and Rubin start observing the universe.
“We will use the observations to make our simulations even more accurate,” Kiessling said. “This will give us more insight into 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 patch of sky, a total of about 0.08 square degrees (approximately equal to a third of the sky covered by a Full Moon). The full simulation, due to be released later this year, will cover an area of 70 square degrees, approximately the area of the sky covered by 350 full moons.
By overlapping them, scientists can learn how to use the best aspects of each telescope: Rubin’s wider view and Roman’s sharper, deeper view. The combination will provide better constraints than researchers from either observatory could derive alone.
“By connecting the simulations together, as we have done, we can make comparisons and see how Roman’s space research will help improve the data from Rubin’s research on the ground,” Heitmann said. “We can explore ways to pick out multiple objects that blend together in Rubin’s images and apply those corrections over its broader coverage.”
Scientists may consider adjusting each telescope’s observation plans or data processing pipelines to promote the combined use of both.
“We have made phenomenal progress in simplifying these pipelines and making them usable,” Kiessling said. A partnership with Caltech/IPAC’s IRSA (Infrared Science Archive) now makes simulated data accessible, so that when researchers access real data in the future, they will already be accustomed to the tools. “Now we want people to start working on the simulations to see what improvements we can make and prepare to use the future data as effectively as possible.”
OpenUniverse, along with other simulation tools being 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’s JPL, DOE’s Argonne, IPAC and several US universities to coordinate with the Roman 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 Roman Space Telescope is operated 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 consisting from scientists from various research institutions. The main industrial partners are BAE Systems, Inc. in Boulder, CO; 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 early construction funding received from private donations through the LSST Discovery Alliance.
Download high-resolution video and images from NASA’s Scientific Visualization Studio
By Ashley Balzer
NASA’s Goddard Space Flight CenterGreenbelt, MD.
Media contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Maryland.