CMU Researchers Help Prepare NASA’s Roman Space Telescope
Heidi Opdyke
- Associate Dean of Marketing and Communications, MCS
- Email opdyke@andrew.cmu.edu
- Phone 412-268-9982
If looking through the Hubble Telescope is peeking through a keyhole, then gazing from the new Nancy Grace Roman Space Telescope is like throwing open a window.
Scheduled to launch Aug. 30, Roman will capture vast swaths of the universe in a single image, helping astronomers discover distant worlds, map hundreds of millions of galaxies and investigate one of science's biggest mysteries: why the universe is expanding faster and faster.
For more than a decade, researchers from Carnegie Mellon University’s McWilliams Center for Cosmology and Astrophysics have helped prepare for Roman’s arrival. Department Head of Physics Rachel Mandelbaum and Professor of Physics Matthew Walker have been part of the teams designing the mission’s specific scientific program, helping determine how to maximize the telescope’s capabilities and preparing the tools scientists will use to analyze its data.
“Roman is exactly the kind of project that benefits from a collaborative approach, not just between institutions but disciplines, and that can provide many long-term research opportunities for postdoctoral, graduate, and undergraduate researchers” Mandelbaum said.
What is special about Roman is its enormous field of view and exceptionally sharp infrared images. Its camera can capture an area of sky about 100 times larger than Hubble’s in a single image in detail. From its position some one million miles from Earth, the telescope will study planets around other stars, trace the formation of galaxies and help scientists better understand the structure and evolution of the universe.
Mapping the invisible universe
Mandelbaum is an international leader in a field known as weak gravitational lensing, a technique that allows scientists to map matter that cannot be seen directly.
As light from distant galaxies travels through the universe, gravity from both visible matter and invisible dark matter bends and stretches that light. By measuring tiny distortions, scientists can create maps of dark matter and better understand how the universe has evolved.
Walker is working to optimize Roman’s ability to detect faint stars and map nearby galaxies with higher accuracy than ever before.
“I can’t stress enough how wonderful these images will be,” Walker said. “We can image stars in the infrared — especially cool stars and distant galaxies — more brightly than they are in the visible part of the spectrum.”
The software and analysis tools being developed by Walker, Mandelbaum and collaborators will help ensure that Roman’s observations can be translated into reliable scientific measurements.
Exploring dark energy
One of Roman’s flagship projects is the High-Latitude Imaging Survey, part of the telescope’s broader High-Latitude Wide-Area Survey.
The survey will catalog hundreds of millions of galaxies across a huge area of sky, providing one of the most detailed maps of the universe ever created. Scientists will use those observations to investigate dark energy and the accelerating expansion of the universe.
Mandelbaum and her collaborators are developing algorithms that will allow researchers to extract precise measurements from Roman’s images and use them to test theories about how the universe works.
Their work is part of the scientific pipeline that will convert Roman’s raw observations into data products that astronomers around the world can use.
The Roman Space Telescope will survey the infrared universe from beyond the orbit of the Moon. Data it gathers will enable scientists to discover detailed information about planetary systems around other stars.
“Roman’s scientific impact will be greatest when its data can be easily used by the entire research community,” Mandelbaum said. “We're building tools that will allow astronomers to make cosmological measurements with publicly-available Roman data and make a start at combining Roman observations with data from Rubin.This is an important step towards a full combination of these data with Euclid and other major surveys. Together, these datasets will give us a much more complete picture of galaxies, dark matter and the evolution of the universe than any one telescope could provide.”
Combining the power of multiple observatories
Among the researchers contributing to that effort is Tae-hyeon Shin, a postdoctoral researcher in Mandelbaum’s lab.
Shin studies galaxy clusters and is developing methods to combine data sets from Roman and the Vera C. Rubin Observatory, which recently began a decade-long survey of the southern sky in June. His goal is to improve estimates of how far away galaxies are from Earth.
Roman will provide infrared images from space, while Rubin will capture observations in visible light from the ground. Together, those measurements will allow astronomers to build detailed “color fingerprints” for galaxies.
Because the universe is expanding, light from distant galaxies becomes stretched toward wavelengths as it travels through space. By measuring those color shifts, astronomers can estimate how far away galaxies are and how long their light has been traveling.
“Rubin is an optical survey and Roman is an infrared survey, so both are synergistic, especially in terms of measuring galaxies’ distances,” Shin said.
Building the tools behind the science
Axel Guinot, a postdoctoral researcher in the McWilliams Center, specializes in image processing and scientific software development.
“Each survey has its own specificities, so we adapt the tools to each given telescope,” Guinot said.
As part of Roman’s project infrastructure team, Guinot is co-leading a group and building computational systems that researchers will use to analyze Roman’s data as well as propose projects for students to contribute to the mission.
“Right now we are testing our methods on simulated images with the best knowledge of the observatory that we have. As soon as it’s in space, it’s going to change everything. Simulations are nice, but it’s not as great as working with actual pictures.”
Recent CMU Ph.D. graduate Federico Berlfein helped prepare for Roman through his dissertation research on factors that can affect image quality. One project focused on the telescope’s filters, specialized materials that select specific wavelengths of light. Because these materials can slightly alter the path of light, scientists need detailed models to understand how those effects influence the final images.
“One of my projects was studying how big this effect was due to the material in the filter, how can we simulate it and how can we model it,” Berlfein said. “We need to understand everything that goes on within the Roman optical system to make what we expect from the telescope more realistic in simulations.”
Berlfein will continue to work as part of the Roman team as a postdoctoral researcher at The Ohio State University in its Center for Cosmology and AstroParticle Physics.
Excitement of launch
The Roman Space Telescope was assembled at NASA’s Goddard Space Flight Center in Maryland before being transported to Kennedy Space Center in Florida for launch.
Before it left Maryland, Guinot traveled to see the telescope in person. He and others in the Mandelbaum Lab plan to attend the launch.
Once Roman reaches space, scientists expect several months of testing and calibration before observations begin.
“I signed up right away to see it,” Guinot said of his trips to Maryland and Florida. “It makes the project more real. Every day I’m mainly coding but to see the telescope and know that it’s going to space gives a sense to the work that you do every day.”
