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Researchers are diving into a synthetic universe to help us better understand the real one. Using supercomputers at the U.S. DOE\u2019s (Department of Energy\u2019s) Argonne National Laboratory in Illinois, scientists have created nearly 4 million simulated images depicting the cosmos as NASA\u2019s 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.<\/p>\n
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 10-terabyte subset of this data, with the remaining 390 terabytes to follow this fall once they\u2019ve been processed.<\/p>\n
\u201cUsing Argonne\u2019s now-retired Theta machine, we accomplished in about nine days what would have taken around 300 years on your laptop,\u201d said Katrin Heitmann, a cosmologist and deputy director of Argonne\u2019s High Energy Physics division who managed the project\u2019s supercomputer time. \u201cThe results will shape Roman and Rubin\u2019s future attempts to illuminate dark matter and dark energy while offering other scientists a preview of the types of things they\u2019ll be able to explore using data from the telescopes.\u201d<\/p>\n
A Cosmic Dress Rehearsal<\/strong> For the first time, this simulation factored in the telescopes\u2019 instrument performance, making it the most accurate preview yet of the cosmos as Roman and Rubin will see it once they start observing. Rubin will begin operations in 2025, and NASA\u2019s Roman will launch by May 2027.<\/p>\n The simulation\u2019s precision is important because scientists will comb through the observatories\u2019 future data in search of tiny features that will help them unravel the biggest mysteries in cosmology.<\/p>\n Roman and Rubin will both explore dark energy \u2013\u2013 the mysterious force thought to be accelerating the universe\u2019s expansion. Since it plays a major role in governing the cosmos, scientists are eager to learn more about it. Simulations like OpenUniverse help them understand signatures that each instrument imprints on the images and iron out data processing methods now so they can decipher future data correctly. Then scientists will be able to make big discoveries even from weak signals.<\/p>\n \u201cOpenUniverse lets us calibrate our expectations of what we can discover with these telescopes,\u201d said Jim Chiang, a staff scientist at DOE\u2019s SLAC National Accelerator Laboratory in Menlo Park, California, who helped create the simulations. \u201cIt gives us a chance to exercise our processing pipelines, better understand our analysis codes, and accurately interpret the results so we can prepare to use the real data right away once it starts coming in.\u201d<\/p>\n Then they\u2019ll continue using simulations to explore the physics and instrument effects that could reproduce what the observatories see in the universe.<\/p>\n Telescopic Teamwork<\/strong> It took a large and talented team from several organizations to conduct such an immense simulation.<\/p>\n \u201cFew people in the world are skilled enough to run these simulations,\u201d said Alina Kiessling, a research scientist at NASA\u2019s Jet Propulsion Laboratory (JPL) in Southern California and the principal investigator of OpenUniverse. \u201cThis massive undertaking was only possible thanks to the collaboration between the DOE, Argonne, SLAC, and NASA, which pulled all the right resources and experts together.\u201d<\/p>\n And the project will ramp up further once Roman and Rubin begin observing the universe.<\/p>\n \u201cWe\u2019ll use the observations to make our simulations even more accurate,\u201d Kiessling said. \u201cThis will give us greater insight into the evolution of the universe over time and help us better understand the cosmology that ultimately shaped the universe.\u201d<\/p>\n The Roman and Rubin simulations cover the same patch of the sky, totaling about 0.08 square degrees (roughly equivalent to a third of the area of sky covered by a full Moon). The full simulation to be released later this year will span 70 square degrees, about the sky area covered by 350 full Moons.<\/p>\n Overlapping them lets scientists learn how to use the best aspects of each telescope \u2013\u2013\u00a0Rubin\u2019s broader view and Roman\u2019s sharper, deeper vision. The combination will yield better constraints than researchers could glean from either observatory alone.<\/p>\n \u201cConnecting the simulations like we\u2019ve done lets us make comparisons and see how Roman\u2019s space-based survey will help improve data from Rubin\u2019s ground-based one,\u201d Heitmann said. \u201cWe can explore ways to tease out multiple objects that blend together in Rubin\u2019s images and apply those corrections over its broader coverage.\u201d<\/p>\n Scientists can consider modifying each telescope\u2019s observing plans or data processing pipelines to benefit the combined use of both.<\/p>\n \u201cWe made phenomenal strides in simplifying these pipelines and making them usable,\u201d Kiessling said. A partnership with Caltech\/IPAC\u2019s IRSA (Infrared Science Archive) makes simulated data accessible now so when researchers access real data in the future, they\u2019ll already be accustomed to the tools. \u201cNow we want people to start working with the simulations to see what improvements we can make and prepare to use the future data as effectively as possible.\u201d<\/p>\n OpenUniverse, along with other simulation tools being developed by Roman\u2019s Science Operations and Science Support centers, will prepare scientists for the large datasets expected from Roman. The project brings together dozens of experts from NASA\u2019s JPL, DOE\u2019s Argonne, IPAC, and several U.S. 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 DOE Office of Science user facility.<\/p>\n The Nancy Grace Roman Space Telescope is managed at NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA\u2019s Jet Propulsion Laboratory and Caltech\/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.<\/p>\n 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.<\/p>\n Download high-resolution video and images from NASA\u2019s Scientific Visualization Studio<\/p>\n By Ashley Balzer
NASA\u2019s Goddard Space Flight Center<\/strong>, Greenbelt, Md.<\/strong><\/p>\n