Roman Space Telescope Could Image 100 Hubble Ultra Deep Fields at Once


One of the Hubble Space Telescope’s most iconic images is the Hubble Ultra Deep Field, which unveiled myriad galaxies across the universe, stretching back to within a few hundred million years of the Big Bang. Hubble peered at a single patch of seemingly empty sky for hundreds of hours beginning in September 2003, and astronomers first unveiled this galaxy tapestry in 2004, with more observations in subsequent years.

NASA’s upcoming Nancy Grace Roman Space Telescope will be able to photograph an area of the sky at least 100 times larger than Hubble with the same crisp sharpness. Among the many observations that will be enabled by this wide view of the cosmos, astronomers are considering the possibility and scientific potential of a Roman Space Telescope “ultra-deep field.” Such an observation could reveal new insights into subjects ranging from star formation during the universe’s youth to the way galaxies cluster together in space.

Roman will enable new science in all areas of astrophysics, from the solar system to the edge of the observable universe. Much of Roman’s observing time will be dedicated to surveys over wide swaths of the sky. However, some observing time will also be available for the general astronomical community to request other projects. A Roman ultra deep field could greatly benefit the scientific community, say astronomers.

“As a community science concept, there could be exciting science returns from ultra-deep field observations by Roman. We would like to engage the astronomical community to think about ways in which they could take advantage of Roman’s capabilities,” said Anton Koekemoer of the Space Telescope Science Institute in Baltimore, Maryland. Koekemoer presented the Roman ultra-deep field idea at the 237th meeting of the American Astronomical Society, on behalf of a group of astronomers spanning more than 30 institutions.

As an example, a Roman ultra-deep field could be similar to the Hubble Ultra Deep Field – looking in a single direction for a few hundred hours to build up an extremely detailed image of very faint, distant objects. Yet while Hubble snagged thousands of galaxies this way, Roman would collect millions. As a result, it would enable new science and vastly improve our understanding of the universe.

Roman Ultra Deep Field Visualization

This composite image illustrates the possibility of a Roman Space Telescope “ultra deep field” observation. In a deep field, astronomers collect light from a patch of sky for an extended period of time to reveal the faintest and most distant objects. This view centers on the Hubble Ultra Deep Field (outlined in blue), which represents the deepest portrait of the universe ever achieved by humankind, at visible, ultraviolet and near-infrared wavelengths. Two insets reveal stunning details of the galaxies within the field. Beyond the Hubble Ultra Deep Field, additional observations obtained over the past two decades have filled in the surrounding space. These wider Hubble observations reveal over 265,000 galaxies, but are much shallower than the Hubble Ultra Deep Field in terms of the most distant galaxies observed. These Hubble images are overlaid on an even wider view using ground-based data from the Digitized Sky Survey. An orange outline shows the field of view of NASA’s upcoming Nancy Grace Roman Space Telescope. Roman’s 18 detectors will be able to observe an area of sky at least 100 times larger than the Hubble Ultra Deep Field at one time, with the same crisp sharpness as Hubble.Credits: NASA, ESA, and A. Koekemoer (STScI); Acknowledgement: Digitized Sky Survey

Structure and history of the universe

Perhaps most exciting is the possibility of studying the very early universe, which corresponds to the most distant galaxies. Those galaxies are also the rarest: for example, only a handful are seen in the Hubble Ultra Deep Field.

Thanks to Roman’s wide field of view and near-infrared data of similar quality to Hubble’s, it could discover many hundreds, or possibly thousands, of these youngest, most distant galaxies, interspersed among the millions of other galaxies. That would let astronomers measure how they group together in space as well as their ages and how their stars have formed.

“Roman would also yield powerful synergies with current and future telescopes on the ground and in space, including NASA’s James Webb Space Telescope and others,” said Koekemoer.

Moving forward in cosmic time, Roman would pick up additional galaxies that existed about 800 million to 1 billion years after the big bang. At that time, galaxies were just beginning to group together into clusters under the influence of dark matter. While researchers have simulated this process of forming large-scale structures, a Roman ultra-deep field would provide real world examples to test those simulations.

In 2003, Hubble captured its iconic Ultra Deep Field image, which changed our understanding of the universe. With 100 times more coverage, imagine what we could learn if the Nancy Grace Roman Space Telescope did the same.Credits: NASA’s Goddard Space Flight CenterDownload high-resolution video and images from NASA’s Scientific Visualization Studio

Star formation over cosmic time

The early universe also experienced a firestorm of star formation. Stars were being born at rates hundreds of times faster than what we see today. In particular, astronomers are eager to study “cosmic dawn” and “cosmic noon,” which together cover a time 500 million to 3 billion years after the big bang when most star formation was happening, as well as when supermassive black holes were most active.

“Because Roman’s field of view is so large, it will be game changing. We would be able to sample not just one environment in a narrow field of view, but instead a variety of environments captured by Roman’s wide-eyed view. This will give us a better sense of where and when star formation was happening,” explained Sangeeta Malhotra of NASA Goddard Space Flight Center in Greenbelt, Maryland. Malhotra is a co-investigator on the Roman science investigation teams working on cosmic dawn, and has led programs that do deep spectroscopy with Hubble, to learn about distant, young galaxies.

Astronomers are eager to measure star formation rates in this distant epoch, which could influence a variety of factors such as the amount of heavy elements observed. Rates of star formation might depend on whether or not a galaxy lies within a large cluster. Roman will be capable of taking faint spectra that will show distinct “fingerprints” of these elements, and give accurate distances (called redshifts) of galaxies.

“Population experts might ask, what differences are there between people who live in big cities, versus those in suburbia, or rural areas? Similarly, as astronomers we can ask, do the most active star forming galaxies live in very clustered regions, or just at the edges of clusters, or do they live in isolation?” Malhotra said.

Big data and machine learning

One of the greatest challenges of the Roman mission will be learning how to analyze the abundance of scientific information in the public datasets that it will produce. In a sense, Roman will create new opportunities not only in terms of sky coverage, but also in data mining.

A Roman ultra-deep field would contain information on millions of galaxies – far too many to be studied by researchers one at a time. Machine learning – a form of artificial intelligence – will be needed to process the massive database. While this is a challenge, it also offers an opportunity. “You could explore completely new questions that you couldn’t previously address,” stated Koekemoer.

“The discovery potential enabled by the huge datasets from the Roman mission could lead to breakthroughs in our understanding of the universe, beyond what we might currently envision,” Koekemoer added. “That could be Roman’s lasting legacy for the scientific community: not only in answering the science questions we think we can address, but also new questions that we have yet to think of.”

Related link: The Astro 2020 white paper by A. Koekemoer et al.

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January 14, 2021 2:56 am

Hopefully the mirror will be TRIPLE-checked this time?

Reply to  Writing Observer
January 14, 2021 7:21 am

It’s hard to account for gravity induced distortions when cooling a lens for nine months.

Reply to  Rhs
January 14, 2021 3:30 pm

That was not the problem with Hubble’s mirror !

Michael S. Kelly
Reply to  Rhs
January 14, 2021 3:58 pm

An infrared telescope mirror (which this primarily is) is a little more forgiving than one firgured for visible light. One quarter wavelength accuracy is the minimum, and many achieve 1/20 th of a wavelength. NGR will span 0.48 to 2.0 microns. If they get the surface accuracy to 1/20 wavelength in the infrared, that’s 0.1 microns. That still gives 1/4.8 accuracy at 0.48 microns (blue), which is acceptable. But figuring for 1/20 in the blue would require a surface accuracy of 0.024 microns, 4.167 times more accurate.

Reply to  Rhs
January 14, 2021 4:10 pm

Which is why they grind the mirror after it has finished cooling.

Gregory Woods
January 14, 2021 3:09 am

When is all of this supposed to happen?

Mark of OKC
Reply to  Gregory Woods
January 14, 2021 7:47 am

tentative 2025 launch date, budget pending.

Joel O'Bryan(@joelobryan)
Reply to  Mark of OKC
January 14, 2021 11:07 am

Libtard’s Green New Deal will probably need the money. The science community has made a Deal with the Devil getting in bed with the Democrat-Marxists.

Reply to  Gregory Woods
January 14, 2021 3:33 pm

Yes, I was wondering how this article managed to miss that detail.
Where is the James Watt ? Maybe they are too embarrassed to even mention that one.

January 14, 2021 7:11 am

Wait, what??
The Romans had space technology?

Reply to  MarkW
January 14, 2021 8:03 am

I was a bit surprised that this article did not contain a paragraph explaining who Nancy Grace Roman was, and why this was named after her.

She was NASA’s Chief of Astronomy throughout the 60s and 70s.

Reply to  MarkW
January 14, 2021 3:35 pm

yes, I guess that title was a bit of scientific click bait.

Reply to  MarkW
January 14, 2021 5:39 pm

Nah. Archimedes invented it first.
The Romans just stole it.

January 14, 2021 7:14 am
Reply to  MarkW
January 15, 2021 5:12 pm

fox news? The claimants to mystical magical prognostications according to murdoch desires?

I would not click their links, period.

Figures nasa finds fewer galaxies. Besides using unenlarged images, they kept their shoes on during their count.

Gary Pearse
January 14, 2021 9:42 am

” At that time, galaxies were just beginning to group together into clusters under the influence of dark matter. ”

Astronomy is joining the club of post normal scientists in climate, medicine, etc. in normalizing what phenomena they ‘feel’ should be there – a perversion of the axiom “Seek and ye shall find.” This deciding what you will find before the research has begun is what happened to social sciences after Marx. Eventually, old guys like me are gone and wifty-poofty concepts like “Dark Matter” precipitate into substantivus.

Reply to  Gary Pearse
January 14, 2021 10:24 am

People like to look for patterns, especially in signals of unknown fidelity, and infer objects. Dark matter fills the role of brown matter regularly injected into climate models, to force a consensus with observable, reproducible reality in a limited frame of reference.

Joel O'Bryan(@joelobryan)
Reply to  n.n
January 14, 2021 11:13 am

The most GCMs effectively make the lower troposphere a molasses atmosphere (highly viscous) to avoid the heat transfer problems of rapid convection flow of heat in order to produce their radiative GH effects. Total junk.

Last edited 1 year ago by joelobryan
Joel O'Bryan(@joelobryan)
Reply to  Gary Pearse
January 14, 2021 11:11 am

The Lambda-CDM (cold mark matter) theory is under severe pressure from lack of obtaining any evidence for its existence other than hypothesized reason galaxies rotate and clump as they do.

CDM theory is now on life-support.

Joel O'Bryan(@joelobryan)
January 14, 2021 11:01 am

The interesting possbilitity is we could actually image our own galaxy the Milky Way and Andromeda in such an ultra deep field view of the universe. We wouldn’t be able to recognize the Milky Way or Andromeda though, because they would be as they were 13 or so billion years ago, not as we see them today. Today we see Andromeda in a direct view from 2 Million light years away with the naked eye as a faint fuzzy patch also known as Messier object 33, or simply M33.

This would be evidence that the universe is manifold and hyper-dimensional, then we could also peer deep enough and see Andromeda as it was 13-14 billion years ago and then even deeper when it was just a few hundred million years old and so on deeper into the folds. This is sort of like a going into a Hall of Mirror-Glass carnival arcade but in mind-blowing hyper dimensions that only mathematics, the kind that Einstein had to learn for his GR formulation, can sort out.

Last edited 1 year ago by joelobryan
Tom Abbott
Reply to  Joel O'Bryan
January 14, 2021 12:23 pm

“The interesting possbilitity is we could actually image our own galaxy the Milky Way and Andromeda in such an ultra deep field view of the universe. We wouldn’t be able to recognize the Milky Way or Andromeda though, because they would be as they were 13 or so billion years ago, not as we see them today.”

I read the other day that one of the Milky Way’s globular clusters is 13.6 billion years old. Maybe it, or something it contained, would be recognizable in a deep image.

Reply to  Joel O'Bryan
January 15, 2021 9:54 am

Sounds a bit like the proposed holographic principle.

michael hart
January 14, 2021 1:08 pm

“However, some observing time will also be available for the general astronomical community to request other projects. A Roman ultra deep field could greatly benefit the scientific community, say astronomers.”

OK, I’m happy to play the cynic here.

They can’t think of enough extra justifications for the cost beyond their own specific desires, “But if the wider scientific community wishes to help us with some extra great reasons then we might give them a small slice of the pie too. Maybe.”

January 14, 2021 5:28 pm

With the same 2.4m aperture as Hubble it will take 100 times longer to capture as many photons per pixel as the Hubble Deep Fields, and since those were 1M second exposures you’re talking 100M seconds, or right about 3 years.

I think this project should be canned. With the advent of the SpaceX Suoer Heavy with an 8m fairing, I’d commission a mirror of that size from the Arizona mirror lab and move this things detector to a new, larger scope. Astronomy has always been about aperture, and for ulta deep wide field imaging that is truer than ever.

MHO anyway.

Tom Abbott
Reply to  MDN
January 15, 2021 6:03 am

Putting bigger telescopes in orbit sounds like a good idea to me. An eight-meter-wide mirror! It can’t happen soon enough.

January 15, 2021 7:38 am

Any bets on which launches first? Webb or Roman?

January 15, 2021 4:56 pm

“Roman Space Telescope Could Image 100 Hubble Ultra Deep Fields at Once”

I always hate simplistic wordings…

A while back on I was reading a thread about a 155mm (6.1″) triplet lens available for a brief period.

A few experienced telescope makers had varying experiences with the lens arrangement.

Perhaps the pinnacle imaged in this thread is the following comment and attachment:

My friend John took this last week – a single 5 min. luminance image centered on Deneb (the North America and Pelican Nebulae are visible in the upper left). (Trees are visible in the lower right corner). I think he had the zoom about halfway, I’m not sure. I was stunned when I saw the full image. –Keith”comment image

Another commenter described this lens as a “light sucking monster”. That is, the lens was capable of capturing light from even weak light sources and imaging that light.

Not, that those small points of light can be enlarged sufficiently to see them in detail.

Last edited 1 year ago by ATheoK
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