This composite image illustrates the possibility of a Roman space telescope ‘ultra deep field’ observation. In a deep field, astronomers for a long time collect light from a piece of air to reveal the faintest and farthest objects. This view focuses on the Hubble Ultra Deep Field (set out in blue), which represents the deepest portrait of the universe ever achieved by mankind, on visible, ultraviolet and near-infrared wavelengths. Two inserts reveal beautiful details of the galaxies in the field.
Outside of the Hubble Ultra Deep Field, additional observations gained over the past two decades have filled the surrounding space. These wider Hubble observations reveal more than 265,000 galaxies, but are much shallower than the Hubble Ultra Deep field in terms of the most distant galaxies.
These Hubble images are overlaid on an even wider image using 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 can detect an air area at least 100 times larger than the Hubble Ultra Deep Field at one time, with the same sharp sharpness as Hubble.
Credit: NASA, ESA and A. Koekemoer (STScI), Recognition: Digitized Sky Survey
In 1995, the Hubble Space Telescope stared at an empty spot in the sky for ten days in a row. The resulting deep field image has captured thousands of stars that have never been seen before. Similar observations have followed since then, including the longest and deepest exposure, the Hubble Ultra Deep Field. Astronomers are now looking ahead to the future and the possibilities that make it possible NASA‘s upcoming Nancy Grace Roman Space Telescope.
The Roman Space Telescope can photograph an airspace 100 times larger than Hubble with the same excellent sharpness. As a result, a Roman Ultra Deep Field would accumulate millions of galaxies, including hundreds dating back just a few hundred million years to the Big Bang. Such an observation would spark new investigations into various scientific fields, from the structure and evolution of the universe to star formation over cosmic time.
This zoom-out animation begins with a view of the Hubble Ultra Deep Field (set out in blue), which is the deepest portrait of the universe ever reached by mankind, at visible, ultraviolet and near-infrared wavelengths. The view then expands to give a wider Hubble survey of the sky (white perimeter), which captured approximately 265,000 galaxies in a large mosaic. As we expand further, we see the Hubble data on a ground view covered using data from the Digitalized Sky Survey.
An orange outline shows the field of view of NASA’s upcoming Nancy Grace Roman Space Telescope. Roman’s 18 detectors can detect an air area at least 100 times larger than the Hubble Ultra Deep Field at one time, with the same sharp sharpness as Hubble.
Credit: NASA, ESA, A. Koekemoer (STScI), and A. Pagan (STScI)
One of Hubble Space Telescopes’ most iconic images is the Hubble Ultra Deep Field, which unveiled countless galaxies across the universe, which within a few hundred million years after the Big explosion. Hubble looked at a single piece of seemingly empty sky for hundreds of hours during September, and astronomers unveiled the galaxy in 2004, with more observations in subsequent years.
NASA’s upcoming Nancy Grace Roman space telescope can photograph an area of the sky at least 100 times larger than Hubble with the same sharp sharpness. Among the many observations made possible by this wide view of the cosmos, astronomers consider the possibility and scientific potential of an “ultra-deep field” of a Roman space telescope. Such an observation could reveal new insights into topics ranging from star formation during the youth of the universe to the way galaxies converge in space.
Novel will enable new science in all areas of astrophysics, from the solar system to the edge of the observable universe. Much of Roman’s observation time will be devoted to surveys over wide areas of the sky. However, there will be some observation time available for the general astronomical community to request other projects. A Roman ultra-deep field could greatly benefit the scientific community, astronomers say.
‘As a community science concept, there could be exciting scientific returns from ultra-deep field observations by Roman. We want to engage the astronomical community to think about ways in which they can harness the capabilities of Roman, ”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.
For example, a Roman ultra-deep field might be similar to the Hubble Ultra Deep Field – a few hundred hours looking in a single direction to build up a highly detailed image of very vague, distant objects. But while Hubble captured thousands of galaxies in this way, Roman would raise millions. As a result, it would enable new science and significantly improve our understanding of the universe.
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. These 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 was able to discover hundreds or possibly thousands of these latest, most distant galaxies interspersed among the millions of other galaxies. In this way, astronomers can measure how they group together in space, as well as their ages and how their stars formed.
“Novel would also produce powerful synergies with current and future telescopes on the ground and in space, including NASA’s James Webb Space Telescope and others,” Koekemoer said.
In cosmic times, Rome would further pick up galaxies that existed about 800 million to 1 billion years after the Big Bang. At that time, galaxies only began to converge in groups under the influence of dark matter. While researchers mimicked this process of forming large-scale structures, a Roman ultra-deep field would provide real-world examples to test those simulations.
Star formation over cosmic time
The early universe also experienced a firestorm of star formation. Stars are born hundreds of times faster than we see today. Astronomers are particularly keen to study ‘cosmic dawn’ and ‘cosmic noon’, which together date from 500 million to 3 billion years after the Big Bang when most star formation took place, as well as the supermassive black holes were most active, study. .
‘Because Roman’s field of vision is so large, it’s going to change game. We would not only be able to sample one environment in a narrow field of view, but rather a variety of environments viewed through Roman’s wide eye. This will give us a better idea of where and when star formation takes place, ”explained Sangeeta Malhotra of the NASA Goddard Space Flight Center in Greenbelt, Maryland. Malhotra is a co-researcher of the Roman scientific research teams engaged in cosmic dawn, and has led programs that do deep spectroscopy with Hubble, to learn more about distant, young galaxies.
Astronomers are eager to measure star formation in this distant time period, which can affect various factors, such as the amount of heavy elements observed. Rates of star formation may depend on whether or not a galaxy lies within a large group. Novel is able to take faint spectra that show clear ‘fingerprints’ of these elements and give accurate distances (called redshifts) of galaxies.
‘Population experts might ask what difference is there between people living in big cities, compared to those in suburbs or rural areas? Just like astronomers, we can ask: do the galaxies that form the strongest live in many grouped regions, or just on the edge of clusters, or do they live in isolation? Malhotra said.
Big data and machine learning
One of the greatest challenges of the Roman mission is to learn how to analyze the abundance of scientific information in the public data sets it will produce. In a sense, Roman will create new opportunities not only in terms of air coverage but also in data mining.
A Roman ultra-deep field contains information on millions of galaxies – far too many to be studied one by one by researchers. Machine learning – a form of artificial intelligence – will be needed to process the massive database. While it is a challenge, it also offers an opportunity. “You can explore completely new questions that you could not handle before,” Koekemoer said.
“The potential for discovery made possible by the enormous data sets of the Roman mission could lead to breakthroughs in our understanding of the universe, beyond what we would currently predict,” Koekemoer added. “It could be Roman long-standing legacy for the scientific community: not only answering the scientific questions we think we can address, but also new questions we still have to think about.”