How the Roman Space Telescope will trace back to the origins of the universe

A new simulation shows how NASA’s Nancy Grace Roman Space Telescope will turn back the cosmic clock when it launches in May 2027, revealing the evolution of the universe in ways not possible before. With his ability to rapidly image vast swathes of space, Roman will help us understand how the universe transformed from a primordial sea of ​​charged particles into the complex web of vast cosmic structures we see today.

“The Hubble and James Webb space telescopes are optimized for studying astronomical objects at depth and up close, so it’s like looking at the universe through a tiny pinhole,” said Aaron Young, a postdoctoral fellow at NASA’s Goddard Space Flight Center. in Greenbelt, Maryland, who led the study. “To solve cosmic mysteries on the largest scales, we need a space telescope that can show a much broader view. This is exactly what Roman was designed to do.”

The combination of the Great Roman Vision, Hubble’s broader wavelength coverage, and Webb’s more detailed observations will provide a more complete picture of the universe.

The simulation covers a two-square-degree section of sky, which is roughly 10 times the apparent size of the full moon and contains more than five million galaxies. The simulation is based on a widely tested model of galaxy formation that represents our current understanding of how the universe works. Using highly efficient technology, the team can simulate tens of millions of galaxies in less than a day, something that would take years using conventional methods. When Roman starts and starts broadcasting real data, scientists will be able to compare that data with a variety of simulations to test their models. This will help reveal the physics of galaxy formation, dark matter – a mysterious substance only observed through gravitational effects – and much more.

A scientific article describing these findings has been published in Monthly notifications to the Royal Astronomical Society of England in December 2022.

In this deep universe simulated view, every point represents a galaxy. The three small squares show Hubble’s field of view, each revealing a different region of the artificial universe. Roman will be able to quickly scan an area as large as the entire zoomed-in image, giving us insight into the largest structures in the universe.
Source: NASA’s Goddard Space Flight Center and A. Young

Explore the cosmic web

Galaxies and galaxy clusters glow in clusters along invisible filaments of dark matter, in a tapestry the size of the visible universe. With a wide enough view of this tapestry, we can see that the large-scale structure of the universe is like a web, with filaments stretching hundreds of millions of miles. light years. Galaxies are found mostly at the intersections of the filaments, with vast “cosmic voids” between all the bright filaments.

This is what the universe looks like now. But if we could send the universe back in time, we would see something completely different.

Instead of giant, fiery stars scattered across galaxies that are farther apart, we would find ourselves immersed in a sea of ​​plasma (charged particles). This primal broth was almost completely homogeneous, but luckily for us, there were little ‘lumps’. Since these clumps were slightly more dense than their surroundings, they had a slightly greater gravitational pull.

Over hundreds of millions of years, the accumulations have attracted more and more material. They grew large enough to form stars, which were gravitationally pulled into the dark matter that makes up the invisible backbone of the universe. Galaxies were born and continued to evolve, eventually emerging planetary systems like ours.

Roman’s panoramic view will help us see what the universe looked like in different phases and fill in many gaps in our understanding. For example, although astronomers have detected “halos” of dark matter that surround galaxies, they aren’t sure how they form. By seeing how gravitational lensing caused by dark matter distorts the appearance of distant objects, Roman will help us understand how halos evolve through cosmic time.

“Simulations like this will be useful in connecting the unprecedented surveys of large galaxies to be conducted by the Roman telescope with the invisible scaffolding of dark matter that defines the distribution of these galaxies,” said Sangeeta Malhotra, an astrophysicist at Goddard. Study co-author of a scientific article.

Look at the bigger picture

Studying such vast cosmic structures with other space telescopes is impractical because it would take hundreds of years of observations to piece together enough images to see such structures.

“Roman will have a unique ability to match the depth of the Hubble Ultra Deep Field, while covering an area of ​​sky many times larger than wide surveys like the Candles survey,” said Young. “This comprehensive view of the early universe will help us understand how representative the images captured by Hubble and Webb are of what it was like at the time.”

Roman’s broad view will also serve as a roadmap that Hubble and Webb can use to focus on areas of interest.

The extensive surveys of the sky by the Romanian telescope will be able to map the universe a thousand times faster than the Hubble telescope. This would be possible because of the observatory’s rigid structure, its fast rotation rate and the telescope’s large field of view. Roman will quickly move from one cosmic goal to another. Once a new target is obtained, the vibrations will quickly stop as potentially unstable structures, such as solar panels, are bolted into place.

“Roman will take about 100,000 images each year,” said Jeffrey Crook, an astrophysicist at Goddard. “Given Roman’s larger field of view, even for powerful telescopes like Hubble or Webb, it would take longer than our lives to cover such a large area of ​​the sky.”

By providing a giant, sharp view of cosmic ecosystems and by working with observatories like Hubble and Webb, Roman will help us solve some of the deepest mysteries in astrophysics.

The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center with participation from NASA’s Jet Propulsion Laboratory (JPL), Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore and a science team made up of various scientists. Research institutes. Major manufacturing partners are Ball Aerospace and Technologies Corporation of Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.

By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Maryland

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