Hubble finds large sample of very distant galaxies

July 25, 2008

New Hubble Space Telescope observations of six spectacular galaxy clusters acting as gravitational lenses have given significant insights into the early stages of the Universe. Scientists have found the largest sample of very distant galaxies seen to date: ten promising candidates thought to lie at a distance of 13 billion light-years (~redshift 7.5).

By using the gravitational magnification from six massive lensing galaxy clusters, the NASA/ESA Hubble Space Telescope has provided scientists with the largest sample of very distant galaxies seen to date. Some of the newly found magnified objects are dimmer than the faintest ones seen in the legendary Hubble Ultra Deep Field, which is usually considered the deepest image of the Universe.

By combining both visible and near-infrared observations from Hubble's Advanced Camera for Surveys (ACS) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS), scientists searched for galaxies that are only visible in near-infrared light. They uncovered 10 candidates believed to lie about 13 billion light-years away (a redshift of approximately 7.5), which means that the light gathered was emitted by the stars when the Universe was still very young - a mere 700 million years old.

"These candidates could well explain one of the big puzzles plaguing astronomy today. We know that the Universe was reionised within the first 5-600 million years after the Big Bang, but we don't know if the ionising energy came from a smaller number of big galaxies or a more plentiful population of tiny ones", said Johan Richard, from the California Institute of Technology. The relatively high number of redshift 7.5 galaxies claimed in this survey suggests that most of the ionising energy was produced by dim and abundant galaxies rather than large, scarce ones.

"The challenge for astronomers is that galaxies beyond a distance of 13 billion light-years (past a redshift of 7) are exceedingly faint and are only visible in the near-infrared - just at the limit of what Hubble can observe" explained Jean-Paul Kneib from the Laboratoire d'Astrophysique de Marseille. This new result was only made possible with some cosmic assistance in the form of gravitational lensing that magnified the light from the distant galaxies enough for Hubble to detect them. A firm confirmation of their distance was beyond even the capabilities of the 10-meter Keck telescope and must await powerful future ground-based telescopes.

First observationally confirmed in 1979, gravitational lenses were predicted by Albert Einstein's theory of General Relativity, a theory that allows astronomers to calculate the path of starlight as it moves through curved space-time. According to the theory, the bending of light is brought about by the presence of matter in the Universe, which causes the fabric of space-time to warp and curve.

Gravitational lensing is the result of this warping of spacetime and is mainly detected around very massive galaxy clusters. Due to the gravitational effect of both the cluster's observable matter and hidden dark matter, the light is bent around the cluster. This bending of light allows the clusters in certain places to act as natural gravitational telescopes that give the light of faint and faraway objects a boost.

Where Earth-bound telescopes fail to detect such faint and distant objects due to the blurring introduced by the Earth's atmosphere, a combination of Hubble's location in space and the magnification of the gravitation lenses provides astronomers with a birds-eye view of these elusive objects.

This technique has already been used numerous times by Hubble and has helped astronomers to find and study many of the most distant known galaxies.

Hubble Information Centre

---

---

	Hubble: A Journey Through Space and Time by Edward Weiler (Author) NASA's first book on the Hubble Space Telescope marks the 20th anniversary of one of history's most important scientific tools. Here is Hubble's great visual legacy to humanity in stunning images that are benchmarks of astronomy and photography. Of the more than 100 classic Hubble images that were selected by NASA's experts, the 20 most significant are accompanied by commentaries by notable scientists. Veteran astronauts from NASA's five remarkable manned missions to maintain the telescope also contribute to this volume, making it an authoritative account of a magnificent scientific achievement. Beyond its scientific contributions, twenty years of Hubble research and imagery--ranging from our planetary neighbors to the edge of time and space--have had a profound impact on the...
	Hubble: Imaging Space and Time (National Geographic) by David Devorkin (Author), Robert Smith (Author) In the spirit of National Geographic’s top-selling Orbit, this large-format, full-color volume stands alone in revealing more than 200 of the most spectacular images from the Hubble Space Telescope during its lifetime, to the very eve of the 2008 final shuttle mission to the telescope. Written by two of the world’s foremost authorities on space history, Hubble: Imaging Space and Time illuminates the solar system’s workings, the expansion of the universe, the birth and death of stars, the formation of planetary nebulae, the dynamics of galaxies, and the mysterious force known as "dark energy." The potential impact of this book cannot be overstressed: The 2008 servicing mission to install new high-powered scientific instruments is especially high profile because the...
	The Universe in a Mirror: The Saga of the Hubble Space Telescope and the Visionaries Who Built It by Robert Zimmerman (Author) The Hubble Space Telescope has produced the most stunning images of the cosmos humanity has ever seen. It has transformed our understanding of the universe around us, revealing new information about its age and evolution, the life cycle of stars, and the very existence of black holes, among other startling discoveries. But it took an amazing amount of work and perseverance to get the first space telescope up and running. The Universe in a Mirror tells the story of this telescope and the visionaries responsible for its extraordinary accomplishments. Robert Zimmerman takes readers behind the scenes of one of the most ambitious scientific instruments ever sent into space. After World War II, astronomer Lyman Spitzer and a handful of scientists waged a fifty-year struggle to build the first...
	Hubble Space Telescope: New Views of the Universe by Mark Voit (Author) How did the universe begin? How big is it? What is it made of? What is its ultimate fate? These are some of the questions that scientists have been investigating with the Hubble Space Telescope since its launch in 1990. Not only is Hubble providing us with an unprecedented amount of information about the universe, but its breathtaking images -- disseminated in the press and over the Internet -- have excited more people around the world than any other images made in the last decade.This fabulous, poster-size paperback on Hubble's dramatic discoveries -- prepared to accompany a major Smithsonian Institution exhibition that will travel across the United States for several years -- presents the awesome Hubble images of nebulae, emerging stars, and other celestial phenomena that have...
	The Heavens Proclaim His Glory: A Spectacular View of Creation Through the Lens of the NASA Hubble Telescope by Thomas Nelson (Author) "I can see how it might be possible for a man to look down upon the earth and be an atheist, but I cannot conceive how he could look up into the heavens and say there is no God."  Abraham Lincoln Our world displays the handiwork of God all around us-in the land and sea, the animals and the plants. But in respect to the sky, the heavens, the universe…there's a realm of beauty and creation man has not been able to witness, until now.  The Heavens Proclaim His Glory is a compilation of stunning photography taken by NASA's Hubble® Telescope capturing striking images of stars, galaxies, cosmic events, planets, and more. Vivid up-close photographs are paired with a romantic Psalm or quote, as well as a short description of the image. The Heavens will open up a whole new world of worship...
	Space, Stars, and the Beginning of Time: What the Hubble Telescope Saw by Elaine Scott (Author) Have you ever wished you could travel back in time?  Or visit a galaxy light-years away?  Or see a star being born? The Hubble telescope has allowed scientists to do just that. The Hubble’s dazzling images have transformed astronomy, shedding light on the deepest mysteries of the cosmos, sparking new discoveries and turning speculation into fact. Its gaze has helped astronomers find new galaxies, look back in time almost to the Big Bang, and verify the existence of dark energy, the mysterious force that is causing the expansion of the universe to accelerate. Through the eye of the Hubble, Elaine Scott skillfully guides readers along the evolution of our universe, investigating a question that was once unanswerable: “Where did we come from?”
	2011 Hubble Space Telescope Calendar by Wyman Publishing (Author) This calendar is filled with stunning images of the universe that surrounds us, captured by the marvelous Hubble Telescope.
	Universe of the Hubble Space Telescope 2013 Calendar by Astrographics (Creator) This remarkable 12" by 12" wall calendar features beautiful images of planets, stars, gaseous nebulae, and galaxies captured by NASA's orbiting Hubble Space Telescope, one of the most important scientific instruments of our time. The images have been digitally processed to reveal the elegant and subtle beauty of the most distant realms of the Universe. Includes accurate and informative descriptions by a professional astronomer, and Astrographics' exclusive Sky Watching Guide.
	Hubble Space Telescope and Its Influence on Astronomy: An entry from Gale's Science and Its Times by Leslie A. Mertz (Author) This digital document is an article from Science and Its Times, brought to you by Gale®, a part of Cengage Learning, a world leader in e-research and educational publishing for libraries, schools and businesses. The length of the article is 1503 words. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. The histories of science, technology, and mathematics merge with the study of humanities and social science in this interdisciplinary reference work. Essays on people, theories, discoveries, and concepts are combined with overviews, bibliographies of primary documents, and chronological elements to offer students a fascinating way to understand the impact of science on the course...
	Picturing the Cosmos: Hubble Space Telescope Images and the Astronomical Sublime by Elizabeth A. Kessler (Author)