 |
|
Hubble finds double Einstein ring
January 11, 2008The NASA/ESA Hubble Space Telescope has revealed a never-before-seen optical alignment in space: a pair of glowing rings, one nestled inside the other like a bull's-eye pattern. The double-ring pattern is caused by the complex bending of light from two distant galaxies strung directly behind a foreground massive galaxy, like three beads on a string.
More than just a novelty, a very rare phenomenon found with the Hubble Space Telescope can offer insight into dark matter, dark energy, the nature of distant galaxies, and even the curvature of the Universe. A double Einstein ring has been found by an international team of astronomers led by Raphael Gavazzi and Tommaso Treu of the University of California, Santa Barbara. The discovery is part of the ongoing Sloan Lens Advanced Camera for Surveys (SLACS) program. They are reporting their results at the 211th meeting of the American Astronomical Society in Austin, Texas, USA. A paper has been submitted to The Astrophysical Journal.
The phenomenon, called gravitational lensing, occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it, in much the same way as a magnifying glass would. When both galaxies are exactly lined up, the light forms a circle, called an "Einstein ring", around the foreground galaxy. If another more distant galaxy lies precisely on the same sightline, a second, larger ring will appear.
The odds of seeing such a special alignment are so small that Tommaso says that they "hit the jackpot" with this discovery.
"Such stunning cosmic coincidences reveal so much about nature. Dark matter is not hidden to lensing," added Leonidas Moustakas of the Jet Propulsion Laboratory in Pasadena, California, USA. "The elegance of this lens is trumped only by the secrets of nature that it reveals."
The massive foreground galaxy is almost perfectly aligned in the sky with two background galaxies at different distances. The foreground galaxy is 3 billion light-years away. The inner ring and outer ring are comprised of multiple images of two galaxies at a distance of 6 billion and approximately 11 billion light-years.
SLACS team member Adam Bolton of the University of Hawaii's Institute for Astronomy in Honolulu first identified the lens in the Sloan Digital Sky Survey (SDSS). "The original signature that led us to this discovery was a mere 500 photons (particles of light) hidden among 500,000 other photons in the SDSS spectrum of the foreground galaxy," commented Bolton.
"The twin rings were clearly visible in the Hubble image", added Tommaso. "When I first saw it I said 'wow, this is insane!' I could not believe it!"
The distribution of dark matter in the foreground galaxies that is warping space to create the gravitational lens can be precisely mapped. In addition, the geometry of the two Einstein rings allowed the team to measure the mass of the middle galaxy precisely to be a value of 1 billion solar masses. The team reports that this is the first measurement of the mass of a dwarf galaxy at cosmological distance (redshift of z=0.6).
A sample of several dozen double rings such as this one would offer a purely independent measure. The comparative radius of the rings could also be used to provide an independent measure of the curvature of space by gravity.
Observations of the cosmic microwave background (a relic from the Big Bang) favour flat geometry. A sample of 50 suitable double Einstein rings would be sufficient to measure the dark matter content of the Universe and the equation of state of the dark energy (a measure of its pressure) to 10 percent precision. Other double Einstein rings could be found with wide-field space telescope sky surveys that are being proposed for the Joint Dark Energy Mission (JDEM) and recently recommended by the National Research Council.
ESA/Hubble Information Centre
The odds of seeing such a special alignment are so small that Tommaso says that they "hit the jackpot" with this discovery.
"Such stunning cosmic coincidences reveal so much about nature. Dark matter is not hidden to lensing," added Leonidas Moustakas of the Jet Propulsion Laboratory in Pasadena, California, USA. "The elegance of this lens is trumped only by the secrets of nature that it reveals."
The massive foreground galaxy is almost perfectly aligned in the sky with two background galaxies at different distances. The foreground galaxy is 3 billion light-years away. The inner ring and outer ring are comprised of multiple images of two galaxies at a distance of 6 billion and approximately 11 billion light-years.
SLACS team member Adam Bolton of the University of Hawaii's Institute for Astronomy in Honolulu first identified the lens in the Sloan Digital Sky Survey (SDSS). "The original signature that led us to this discovery was a mere 500 photons (particles of light) hidden among 500,000 other photons in the SDSS spectrum of the foreground galaxy," commented Bolton.
"The twin rings were clearly visible in the Hubble image", added Tommaso. "When I first saw it I said 'wow, this is insane!' I could not believe it!"
The distribution of dark matter in the foreground galaxies that is warping space to create the gravitational lens can be precisely mapped. In addition, the geometry of the two Einstein rings allowed the team to measure the mass of the middle galaxy precisely to be a value of 1 billion solar masses. The team reports that this is the first measurement of the mass of a dwarf galaxy at cosmological distance (redshift of z=0.6).
A sample of several dozen double rings such as this one would offer a purely independent measure. The comparative radius of the rings could also be used to provide an independent measure of the curvature of space by gravity.
Observations of the cosmic microwave background (a relic from the Big Bang) favour flat geometry. A sample of 50 suitable double Einstein rings would be sufficient to measure the dark matter content of the Universe and the equation of state of the dark energy (a measure of its pressure) to 10 percent precision. Other double Einstein rings could be found with wide-field space telescope sky surveys that are being proposed for the Joint Dark Energy Mission (JDEM) and recently recommended by the National Research Council.
ESA/Hubble Information Centre
Hubble Space Telescope News and Current Hubble Space Telescope Events RSSClash of clusters provides new dark matter clue
A powerful collision between galaxy clusters has been captured by the NASA/ESA Hubble Space Telescope and NASA's Chandra X-ray Observatory. This clash of clusters provides striking evidence for dark matter and insight into its properties.
Hubble sees magnetic monster in erupting galaxy
The Hubble Space Telescope has found the answer to a long-standing puzzle by resolving giant but delicate filaments shaped by a strong magnetic field around the active galaxy NGC 1275. It is the most striking example of the influence of these immense tentacles of extragalactic magnetic fields, say researchers.
Hubble unveils colourful star birth region on 100 000th orbit milestone
In commemoration of the NASA/ESA Hubble Space Telescope completing its 100 000th orbit around the Earth in its 18th year of exploration and discovery, scientists have aimed Hubble to take a snapshot of a dazzling region of celestial birth and renewal.
'Cosmic ghost' discovered by volunteer astronomer
When Yale astrophysicist Kevin Schawinski and his colleagues at Oxford University enlisted public support in cataloguing galaxies, they never envisioned the strange object Hanny van Arkel found in archived images of the night sky.
Caltech astronomers describe the bar scene at the beginning of the universe
Bars abound in spiral galaxies today, but this was not always the case. A group of 16 astronomers, led by Kartik Sheth of NASA's Spitzer Science Center at the California Institute of Technology, has found that bars tripled in number over the past seven billion years, indicating that spiral galaxies evolve in shape.
Hubble finds large sample of very distant galaxies
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).
Hubble's sweeping view of the Coma Galaxy Cluster
The NASA/ESA Hubble Space Telescope captures the magnificent starry population of the Coma Cluster of Galaxies, one of the densest known galaxy collections in the Universe.
Team hopes to use new technology to search for ETs
A Johns Hopkins astronomer is a member of a team briefing fellow scientists about plans to use new technology to take advantage of recent, promising ideas on where to search for possible extraterrestrial intelligence in our galaxy.
Astronomers Weigh the Coldest Brown Dwarfs with Astronomy's Sharpest Eyes
Astronomers have used ultrasharp images obtained with the Keck Telescope and Hubble Space Telescope to determine for the first time the masses of the coldest class of "failed stars," a.k.a. brown dwarfs.
Hubble, Keck images show continued turbulence in Jupiter's atmosphere
Increased turbulence and storms first observed on Jupiter more than two years ago are still raging, according to astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii, who snapped high-resolution pictures of the planet earlier this month.
More Hubble Space Telescope News Articles
 | The Universe in a Mirror: The Saga of the Hubble Space Telescope and the Visionaries Who Built It by Robert Zimmerman 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. The Universe in a Mirror tells the story of this telescope and the visionaries... |
 | Hubble: The Mirror on the Universe by Robin Kerrod, Carole Stott The latest photos from Hubble's recent discoveries, with fascinating new and updated information. After 17 years, 25,000 astronomical targets and more than 700,000 images, the Hubble Space Telescope (HST) continues to return images and data that amaze astronomers. Within the past few months alone, the Hubble has revealed a gold mine of just-formed star systems in the newborn Universe,... |
 | Hubble: 15 Years of Discovery by Lars Lindberg Christensen, Robert A. Fosbury Hubble: 15 Years of Discovery forms a key element of the European Space Agency's 15th anniversary celebration activities for the 1990 launch of the NASA/ESA Hubble Space Telescope. As an observatory in space, Hubble is one of the most successful scientific projects of all time, both in terms of scientific output and its immediate public appeal. Hubble continues to have an enormous impact by... |
 | Hubble Space Telescope: New Views of the Universe by Mark Voit In April 1990, the space shuttle Discovery carried the Hubble Space Telescope to an altitude of some 600 kilometers above the Earth, where it has since been delivering images of the distant heavens to scientists below. Despite disappointing early results--the telescope's mirror and camera were revealed to have significant flaws, which were quickly repaired--Hubble has yielded extraordinary views,... |
 | Space Views from the Hubble Telescope 2009 Wall Calendar by Pomegranate Three and a half centuries after Galileo's revolutionary explorations of the night sky, the Hubble Space Telescope has lifted astronomers still closer to the stars. Accompanying each of this calendar's twelve Hubble images is a concise description of the celestial phenomenon depicted. The calendar also notes important dates in the history of space exploration, as well as current astronomical... |
 | The Hubble Wars: Astrophysics Meets Astropolitics in the Two-Billion-Dollar Struggle over the Hubble Space Telescope, With a New Preface by Eric J. Chaisson The Hubble Space Telescope is the largest, most complex, and most powerful observatory ever deployed in space, designed to allow astronomers to look far back into our own cosmic past with unprecedented clarity. Yet from its launch in 1990, when it was discovered that a flawed mirror was causing severe "myopia" and sending fuzzy images back to Earth, the HST has been at the center of a... |
 | State of the Universe 2008: New Images, Discoveries, and Events (Springer Praxis Books / Popular Astronomy) by Martin Ratcliffe The aim of the State of the Universe annuals is to provide an annual astronomy review suitable for the popular science level reader to be published every September in a format that will be suitable for, and appeal to, the Christmas market. The book will cover all major astronomical news on topics beyond the Solar System and place them in the context of the longer term goals of astronomers and... |
 | Destination: Space by Seymour Simon Exceptional nonfiction for children from two of the most trusted names in science education: Seymour Simon and the Smithsonian Institution.... |
 | Adventures in Space: The Flight to Fix the Hubble by Elaine Scott |
 | New Cosmic Horizons: Space Astronomy from the V2 to the Hubble Space Telescope by David Leverington New Cosmic Horizons tells the extraordinary story of space-based astronomy since the Second World War. Starting with the launch of the V2 rocket in 1946, this book explores the triumphs of space experiments and spacecraft designs and the amazing astronomical results that they have produced. David Leverington examines the fascinating way in which the changing political imperatives of the United... |
| © 2008 BrightSurf.com |