Hubble Astronomers Assemble Wide View of the Evolving Universe

Image contains 265,000 galaxies that stretch billions of years back in time.


  • newswise-fullscreen Hubble Astronomers Assemble Wide View of the Evolving Universe

    Credit: NASA, ESA, G. Illingworth and D. Magee (University of California, Santa Cruz), K. Whitaker (University of Connecticut), R. Bouwens (Leiden University), P. Oesch (University of Geneva,) and the Hubble Legacy Field team

    This Hubble Space Telescope image represents the largest, most comprehensive "history book" of galaxies in the universe. The image, a combination of nearly 7,500 separate Hubble exposures, represents 16 years' worth of observations. The ambitious endeavor, called the Hubble Legacy Field, includes several Hubble deep-field surveys, including the eXtreme Deep Field (XDF), the deepest view of the universe. The wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time. The image mosaic presents a wide portrait of the distant universe and contains roughly 265,000 galaxies. They stretch back through 13.3 billion years of time to just 500 million years after the universe's birth in the big bang. The tiny, faint, most distant galaxies in the image are similar to the seedling villages from which today's great galaxy star-cities grew. The faintest and farthest galaxies are just one ten-billionth the brightness of what the human eye can see. The wider view contains about 30 times as many galaxies as in the Hubble Ultra Deep Field, taken in 2004. The new portrait, a mosaic of multiple snapshots, covers almost the width of the full Moon. Lying in this region is the XDF, which penetrated deeper into space than this legacy field view. However, the XDF field covers less than one-tenth of the full Moon's diameter.

  • newswise-fullscreen Hubble Astronomers Assemble Wide View of the Evolving Universe

    Credit: NASA, ESA, G. Illingworth and D. Magee (University of California, Santa Cruz), K. Whitaker (University of Connecticut), R. Bouwens (Leiden University), P. Oesch (University of Geneva), and the Hubble Legacy Field team

    This Hubble Space Telescope image represents a portion of the Hubble Legacy Field, one of the widest views of the universe ever made. The image, a combination of thousands of snapshots, represents 16 years' worth of observations. The Hubble Legacy Field includes observations taken by several Hubble deep-field surveys, including the eXtreme Deep Field (XDF), the deepest view of the universe. The wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time. The cropped image mosaic presents a wide portrait of the distant universe and contains roughly 200,000 galaxies. They stretch back through 13.3 billion years of time to just 500 million years after the universe's birth in the big bang.

  • newswise-fullscreen Hubble Astronomers Assemble Wide View of the Evolving Universe

    Credit: Hubble Legacy Field Image: NASA, ESA, and G. Illingworth and D. Magee (University of California, Santa Cruz); Moon Image: NASA, GSFC, and Arizona State University

    This graphic compares the dimensions of the Hubble Legacy Field on the sky with the angular size of the Moon. The Hubble Legacy Field is one of the widest views ever taken of the universe with Hubble. The new portrait, a mosaic of nearly 7,500 exposures, covers almost the width of the full Moon. The Moon and the Legacy Field each subtend about an angle of one-half a degree on the sky (or half the width of your forefinger held at arm's length). Astronomers assembled the image from 16 years' worth of Hubble observations. The image combines several Hubble deep-field surveys. The wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time.

  • newswise-fullscreen Hubble Astronomers Assemble Wide View of the Evolving Universe

    Credit: NASA, ESA, G. Illingworth and D. Magee (University of California, Santa Cruz), K. Whitaker (University of Connecticut), R. Bouwens (Leiden University), P. Oesch (University of Geneva), and the Hubble Legacy Field team

    This image shows the sizes and locations within the Hubble Legacy Field of the two areas that Hubble first studied in this region, the Great Observatories Origins Deep Survey (GOODS) and the Hubble Ultra Deep Field (HUDF), along with the deepest image ever taken by Hubble, the eXtreme Deep Field (XDF). The Hubble Legacy Field is one of the widest views ever taken of the universe with Hubble. Astronomers assembled the image from 16 years' worth of Hubble observations. The Hubble Legacy Field image combines many Hubble field surveys, including the iconic original HUDF and the first wide-field GOODS, as well as the XDF. The image's wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time. The wide view contains about 30 times as many galaxies as in the HUDF. The new portrait, a mosaic of 7,500 exposures, covers almost the width of the full Moon.

  • newswise-fullscreen Hubble Astronomers Assemble Wide View of the Evolving Universe

    Credit: NASA, ESA, G. Illingworth and D. Magee (University of California, Santa Cruz, K. Whitaker (University of Connecticut), R. Bouwens (Leiden University), P. Oesch (University of Geneva), and the Hubble Legacy Field team

    This graphic reveals close-up images of 15 galaxies from the 265,000 galaxies in the Hubble Legacy Field. The galaxies are scattered across time, from 550 million years ago to 13 billion years ago. Their light is just arriving at Earth now, after crossing space for billions of years. This collection of images allows astronomers to look back in time to see galaxies when they were very young, in the earliest epochs of the universe. The universe is 13.8 billion years old. The top panel of snapshots shows mature "adult" galaxies; the middle panel shows galaxies in their "teenage" years when they are growing and changing dramatically; and the bottom panel shows small, youthful galaxies. The "look-back time" is at the bottom of each image. The snapshot in the top panel at upper left reveals a fully developed spiral galaxy teeming with stars. The galaxy is shown as it appeared just 550 million years ago. In the bottom panel at lower right is a tiny, young, red galaxy from the universe's early days. The barely visible galaxy appears red because its light has been stretched to longer, redder wavelengths due to the expansion of space. This galaxy existed during a time when the cosmos was just 6% of its current age. Light from this galaxy traveled for 13 billion years to reach Earth.

Newswise —

FOR RELEASE: 10:00 a.m. (EDT) May 2, 2019

RELEASE: STScI-PR19-17

HUBBLE ASTRONOMERS ASSEMBLE WIDE VIEW OF THE EVOLVING UNIVERSE

Astronomers have put together the largest and most comprehensive "history book" of galaxies into one single image, using 16 years' worth of observations from NASA's Hubble Space Telescope.

The deep-sky mosaic, created from nearly 7,500 individual exposures, provides a wide portrait of the distant universe, containing 265,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the big bang. The faintest and farthest galaxies are just one ten-billionth the brightness of what the human eye can see. The universe's evolutionary history is also chronicled in this one sweeping view. The portrait shows how galaxies change over time, building themselves up to become the giant galaxies seen in the nearby universe.

This ambitious endeavor, called the Hubble Legacy Field, also combines observations taken by several Hubble deep-field surveys, including the eXtreme Deep Field (XDF), the deepest view of the universe. The wavelength range stretches from ultraviolet to near-infrared light, capturing the key features of galaxy assembly over time.

"Now that we have gone wider than in previous surveys, we are harvesting many more distant galaxies in the largest such dataset ever produced by Hubble," said Garth Illingworth of the University of California, Santa Cruz, leader of the team that assembled the image. "This one image contains the full history of the growth of galaxies in the universe, from their time as 'infants' to when they grew into fully-fledged 'adults.'

No image will surpass this one until future space telescopes are launched. "We've put together this mosaic as a tool to be used by us and by other astronomers," Illingworth added. "The expectation is that this survey will lead to an even more coherent, in-depth, and greater understanding of the universe's evolution in the coming years."

The image yields a huge catalog of distant galaxies. "Such exquisite high-resolution measurements of the numerous galaxies in this catalog enable a wide swath of extragalactic study," said catalog lead researcher Katherine Whitaker of the University of Connecticut, in Storrs. "Often, these kinds of surveys have yielded unanticipated discoveries which have had the greatest impact on our understanding of galaxy evolution."

Galaxies are the "markers of space," as astronomer Edwin Hubble once described them a century ago. Galaxies allow astronomers to trace the expansion of the universe, offer clues to the underlying physics of the cosmos, show when the chemical elements originated, and enable the conditions that eventually led to the appearance of our solar system and life.

This wider view contains about 30 times as many galaxies as in the previous deep fields. The new portrait, a mosaic of multiple snapshots, covers almost the width of the full Moon. The XDF, which penetrated deeper into space than this wider view, lies in this region, but it covers less than one-tenth of the full Moon's diameter. The Legacy Field also uncovers a zoo of unusual objects. Many of them are the remnants of galactic "train wrecks," a time in the early universe when small, young galaxies collided and merged with other galaxies.

Assembling all of the observations was an immense task. The image comprises the collective work of 31 Hubble programs by different teams of astronomers. Hubble has spent more time on this tiny area than on any other region of the sky, totaling more than 250 days, representing nearly three-quarters of a year.

"Our goal was to assemble all 16 years of exposures into a legacy image," explained Dan Magee, of the University of California, Santa Cruz, the team's data processing lead. "Previously, most of these exposures had not been put together in a consistent way that can be used by any researcher. Astronomers can select the data in the Legacy Field they want and work with it immediately, as opposed to having to perform a huge amount of data reduction before conducting scientific analysis."

The image, along with the individual exposures that make up the new view, is available to the worldwide astronomical community through the Mikulski Archive for Space Telescopes (MAST). MAST, an online database of astronomical data from Hubble and other NASA missions, is located at the Space Telescope Science Institute in Baltimore, Maryland.

The Hubble Space Telescope has come a long way in taking ever deeper "core samples" of the distant universe. After Hubble's launch in 1990, astronomers debated if it was worth spending a chunk of the telescope's time to go on a "fishing expedition" to take a very long exposure of a small, seemingly blank piece of sky. The resulting Hubble Deep Field image in 1995 captured several thousand unseen galaxies in one pointing. The bold effort was a landmark demonstration and a defining proof-of-concept that set the stage for future deep field images. In 2002, Hubble's Advanced Camera for Surveys went even deeper to uncover 10,000 galaxies in a single snapshot. Astronomers used exposures taken by Hubble's Wide Field Camera 3 (WFC3), installed in 2009, to assemble the eXtreme Deep Field snapshot in 2012. Unlike previous Hubble cameras, the telescope's WFC3 covers a broader wavelength range, from ultraviolet to near-infrared.

This new image mosaic is the first in a series of Hubble Legacy Field images. The team is working on a second set of images, totaling more than 5,200 Hubble exposures, in another area of the sky. In the future, astronomers hope to broaden the multiwavelength range in the legacy images to include longer-wavelength infrared data and high-energy X-ray observations from two other NASA Great Observatories, the Spitzer Space Telescope and Chandra X-ray Observatory.

The vast number of galaxies in the Legacy Field image are also prime targets for future telescopes. "This will really set the stage for NASA's planned Wide Field Infrared Survey Telescope (WFIRST)," Illingworth said. "The Legacy Field is a pathfinder for WFIRST, which will capture an image that is 100 times larger than a typical Hubble photo. In just three weeks' worth of observations by WFIRST, astronomers will be able to assemble a field that is much deeper and more than twice as large as the Hubble Legacy Field."

In addition, NASA's upcoming James Webb Space Telescope will allow astronomers to push much deeper into the legacy field to reveal how the infant galaxies actually grew. Webb's infrared coverage will go beyond the limits of Hubble and Spitzer to help astronomers identify the first galaxies in the universe.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For more information about the Hubble Legacy Field and Hubble telescope, visit:

http://hubblesite.org/news_release/news/2019-17

http://www.nasa.gov/hubble

http://www.spacetelescope.org/news/heic1909

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu

Garth Illingworth
University of California, Santa Cruz; UCO/Lick Observatory, Santa Cruz, California
831-459-2843
gdi@ucolick.org

 

 


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