 |
|
First Stars Seen In Distant Galaxies
April 02, 2005UK and US astronomers have used the Spitzer Space Telescope and the Hubble Space Telescope to detect light coming from the first stars to form in some of the most distant galaxies yet seen.
Speaking on Wednesday 6 April at the RAS National Astronomy Meeting in Birmingham, Dr. Andrew Bunker (University of Exeter) will discuss new evidence that the formation of the first galaxies may have got underway earlier than previously thought.
This observational work using infrared images from Spitzer Space Telescope is essential, since theoretical predictions for the history of star formation in the early Universe are highly uncertain.
The team, led by Bunker and graduate student Laurence Eyles (University of Exeter), used Hubble Space Telescope data to identify remote galaxies that were suitable for further study. They then analysed archived images taken at infrared wavelengths with NASA's Spitzer Space Telescope.
These images, obtained as part of the 'Great Observatory Origins Deep Survey' (GOODS) project and the Hubble 'Ultra Deep Field' (UDF), covered a part of the southern sky known as the constellation of Fornax (the Oven).
"We used the images from the Hubble Ultra Deep Field to identify objects likely to be galaxies 95 per cent of the way across the observable Universe," explained Bunker. "These images are our most sensitive picture of the Universe so far, and they enabled us to discover the faintest objects yet."
Intervening gas clouds absorbed the light they emitted at visible wavelengths long before it reached Earth, but their infrared light can still be detected - and it is their infrared 'colours' which led the researchers to believe that they lie at such immense distances.
Confirmation of their extreme remoteness was provided by the 10-metre Keck telescopes in Hawaii, the largest optical telescopes in the world.
"We proved these galaxies are indeed among the most distant known by using the Keck telescopes to take a spectrum," said Dr. Elizabeth Stanway (University of Wisconsin- Madison).
The Keck spectra showed that the galaxies have redshifts of about 6, which means they are so far away that light from them has taken about 13 billion years to reach us. Telescopes show them as they were when the Universe was less than a billion years old - eight billion years before the Earth and Sun formed.
The next step was to learn more about the stars within these most distant galaxies by studying new infrared images of this region of space taken by Spitzer.
"The Hubble images tell us about the new-born stars, but the new infrared images taken with the Spitzer Space Telescope give us extra information about the light that comes from older stars within these distant galaxies," said Laurence Eyles, who studied the Spitzer images of these objects as part of his research for a doctorate at Exeter.
"This is very important, because it tells us that some of these galaxies are already 300 million years old when the Universe is very young."
"It could be that these were some of the first galaxies to be born," said Michelle Doherty (Institute of Astronomy, Cambridge).
Using the Spitzer images, the team was able to weigh the stars in these galaxies by studying the starlight.
"It seems that in a couple of cases these early galaxies are nearly as massive as galaxies we see around us today, which is a bit surprising when the theory is that galaxies start small and grow by colliding and merging with other galaxies," said Dr. Mark Lacy (Spitzer Science Center).
"The real puzzle is that these galaxies seem to be already quite old when the Universe was only about 5 per cent of its current age," commented Professor Richard Ellis of Caltech. "This means star formation must have started very early in the history of the Universe - earlier than previously believed."
The light from these first stars to ignite could have ended the Dark Ages of the Universe when the galaxies first 'turned on'. It is also likely to have caused the gas between the galaxies to be blasted by starlight - the 'reionisation' which has been detected in the cosmic microwave background by the WMAP satellite.
The results from WMAP and the Hubble Ultra Deep Field complement the new work done by Bunker's team with the Spitzer data. Taken together, they suggest that the Dark Ages ended sometime between 200 and 500 million years after the Big Bang, when the first stars were born.
A paper on these results has been submitted for publication in the Monthly Notices of the Royal Astronomical Society.
Royal Astronomical Society (RAS)
The team, led by Bunker and graduate student Laurence Eyles (University of Exeter), used Hubble Space Telescope data to identify remote galaxies that were suitable for further study. They then analysed archived images taken at infrared wavelengths with NASA's Spitzer Space Telescope.
These images, obtained as part of the 'Great Observatory Origins Deep Survey' (GOODS) project and the Hubble 'Ultra Deep Field' (UDF), covered a part of the southern sky known as the constellation of Fornax (the Oven).
"We used the images from the Hubble Ultra Deep Field to identify objects likely to be galaxies 95 per cent of the way across the observable Universe," explained Bunker. "These images are our most sensitive picture of the Universe so far, and they enabled us to discover the faintest objects yet."
Intervening gas clouds absorbed the light they emitted at visible wavelengths long before it reached Earth, but their infrared light can still be detected - and it is their infrared 'colours' which led the researchers to believe that they lie at such immense distances.
Confirmation of their extreme remoteness was provided by the 10-metre Keck telescopes in Hawaii, the largest optical telescopes in the world.
"We proved these galaxies are indeed among the most distant known by using the Keck telescopes to take a spectrum," said Dr. Elizabeth Stanway (University of Wisconsin- Madison).
The Keck spectra showed that the galaxies have redshifts of about 6, which means they are so far away that light from them has taken about 13 billion years to reach us. Telescopes show them as they were when the Universe was less than a billion years old - eight billion years before the Earth and Sun formed.
The next step was to learn more about the stars within these most distant galaxies by studying new infrared images of this region of space taken by Spitzer.
"The Hubble images tell us about the new-born stars, but the new infrared images taken with the Spitzer Space Telescope give us extra information about the light that comes from older stars within these distant galaxies," said Laurence Eyles, who studied the Spitzer images of these objects as part of his research for a doctorate at Exeter.
"This is very important, because it tells us that some of these galaxies are already 300 million years old when the Universe is very young."
"It could be that these were some of the first galaxies to be born," said Michelle Doherty (Institute of Astronomy, Cambridge).
Using the Spitzer images, the team was able to weigh the stars in these galaxies by studying the starlight.
"It seems that in a couple of cases these early galaxies are nearly as massive as galaxies we see around us today, which is a bit surprising when the theory is that galaxies start small and grow by colliding and merging with other galaxies," said Dr. Mark Lacy (Spitzer Science Center).
"The real puzzle is that these galaxies seem to be already quite old when the Universe was only about 5 per cent of its current age," commented Professor Richard Ellis of Caltech. "This means star formation must have started very early in the history of the Universe - earlier than previously believed."
The light from these first stars to ignite could have ended the Dark Ages of the Universe when the galaxies first 'turned on'. It is also likely to have caused the gas between the galaxies to be blasted by starlight - the 'reionisation' which has been detected in the cosmic microwave background by the WMAP satellite.
The results from WMAP and the Hubble Ultra Deep Field complement the new work done by Bunker's team with the Spitzer data. Taken together, they suggest that the Dark Ages ended sometime between 200 and 500 million years after the Big Bang, when the first stars were born.
A paper on these results has been submitted for publication in the Monthly Notices of the Royal Astronomical Society.
Royal Astronomical Society (RAS)
Galaxies Current Events and Galaxies News RSSStars stop forming when big galaxies collide
Astronomers studying new images of a nearby galaxy cluster have found evidence that high-speed collisions between large elliptical galaxies may prevent new stars from forming, according to a paper to be published in a November 2008 issue of The Astrophysical Journal Letters.
More star births than astronomers have calculated
The "birth rate" for stars is certainly not easy to determine. Distances in the universe are far too great for astronomers to be able to count all the newly formed celestial bodies with the aid of a telescope.
Young Galaxy's Magnetism Surprises Astronomers
Astronomers have made the first direct measurement of the magnetic field in a young, distant galaxy, and the result is a big surprise.
First detection of magnetic field in distant galaxy produces a surprise
Using a powerful radio telescope to peer into the early universe, a team of California astronomers has obtained the first direct measurement of a nascent galaxy's magnetic field as it appeared 6.5 billion years ago.
BOSS: the Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey (SDSS) uses a 2.5-meter telescope with a wider field of view than any other large telescope, located on a mountaintop in New Mexico called Apache Point and devoted solely to mapping the universe.
Immigrant Sun: Our star could be far from where it started in Milky Way
A long-standing scientific belief holds that stars tend to hang out in the same general part of a galaxy where they originally formed. Some astrophysicists have recently questioned whether that is true, and now new simulations show that, at least in galaxies similar to our own Milky Way, stars such as the sun can migrate great distances.
Yale Astronomer Discovers Upper Mass Limit for Black Holes
here appears to be an upper limit to how big the universe's most massive black holes can get, according to new research led by a Yale University astrophysicist.
1843 stellar eruption may be new type of star explosion
Eta Carinae, the galaxy's biggest, brightest and perhaps most studied star after the sun, has been keeping a secret: Its giant outbursts appear to be driven by an entirely new type of stellar explosion that is fainter than a typical supernova and does not destroy the star.
New virtual telescope zooms in on Milky Way's super-massive black hole
An international team, led by astronomers at the MIT Haystack Observatory, has obtained the closest views ever of what is believed to be a super-massive black hole at the center of the Milky Way galaxy.
Galaxy Zoo -- an Internet superstar
Since Galaxy Zoo's launch in July 2007, some 150,000 members of the public, inspired by the opportunity to be the first to see and classify a galaxy, have helped professional astronomers via this on-line mass-participation project to carry out real scientific research.
More Galaxies Current Events and Galaxies News Articles
 | The Hitchhiker's Guide to the Galaxy by Douglas Adams "IRRESISTIBLE!"--The Boston GlobeSeconds before the Earth is demolished to make way for a galactic freeway, Arthur Dent is plucked off the planet by his friend Ford Prefect, a researcher for the revised edition of The Hitchhiker's Guide to the Galaxy who, for the last fifteen years, has been posing as an out-of-work actor.Together this dynamic pair begin a journey through space aided by quotes... |
 | Super Mario Galaxy: Prima Official Game Guide by Fletcher Black •Find all 120 stars that unlock the super-secret ending.•Full-color maps give you the layout of the galaxy before you even blast off.•Clothes make the Mario--all of the hero's newest suits detailed.•Locate tons of hidden 1-Up Mushrooms to keep Mario in action.•Mario poster... |
 | The Ultimate Hitchhiker's Guide to the Galaxy by Douglas Adams At last in paperback in one complete volume, here are the five classic novels from Douglas Adams’s beloved Hitchiker series.The Hitchhiker’s Guide to the GalaxySeconds before the Earth is demolished for a galactic freeway, Arthur Dent is saved by Ford Prefect, a researcher for the revised Guide. Together they stick out their thumbs to the stars and begin a wild journey through time and... |
 | The Hitchhiker's Guide to the Galaxy, 25th Anniversary Edition by Douglas Adams How shall we begin?This is the story of a book called The Hitchhiker’s Guide to the Galaxy—not an Earth book, never published on Earth and, until the terrible catastrophe occurred, never seen or even heard of by any Earthman. Nevertheless, a wholly remarkable book.orThis is the story of The Hitchhiker’s Guide to the Galaxy, a number-one best seller in England, a weekly radio series with... |
 | Galaxy in Flames (Horus Heresy) by Ben Counter Having recovered from his grievous injuries, Warmaster Horus leads the triumphant Imperial forces against the rebel world of Isstvan III. Though the rebels are swiftly crushed, Horus's treachery is finally revealed as the planet is razed by virus bombs, and Space Marines turn on their battle-brothers in the most bitter struggle... |
 | Star Wars: A Pop-Up Guide to the Galaxy by Matthew Reinhart Sabuda and Reinhart Studios have created another spectacular pop-up book for George Lucas's epic STAR WARS movies! Bestselling pop-up artist and engineer Matthew Reinhart has designed a thirtieth anniversary commemorative edition that comes packed with a variety of novelty features -- pop-ups, working light sabers, pull tabs, and other interactive looks at the exciting and popular movies. This... |
 | The Internet Galaxy: Reflections on the Internet, Business, and Society (Clarendon Lectures in Management Studies) by Manuel Castells Manuel Castells is one of the world's leading thinkers on the new information age, hailed by The Economist as "the first significant philosopher of cyberspace," and by Christian Science Monitor as "a pioneer who has hacked out a logical, well-documented, and coherent picture of early 21st century civilization, even as it rockets forward largely in a blur." Now, in The Internet Galaxy, this... |
 | Sculpting a Galaxy: Inside the Star Wars Model Shop by Lorne Peterson From the producers of the acclaimed Dressing a Galaxy: The Costumes of Star Wars comes an inside look at the secrets behind the saga’s artful models and sculptures. Lorne Peterson, model and sculpture designer for the entire Star Wars saga, takes us on a journey through the intricate process of crafting and sculpting the models from sketch to screen and the artistry behind the dazzling results.... |
 | Threats of the Galaxy (Star Wars Accessory) by Rodney Thompson, Eric Cagle, Gary Astleford, Robert J. Schwalb, John Snead, Patrick Stutzman Ready-to-play characters, creatures, and droids for your Star Wars campaign.This supplement gives Gamemasters an assortment of galactic denizens to populate their Star Wars Roleplaying Game adventures. Nowhere will you find a more useful hive of scum and villainy! This book presents scores of nefarious characters, fearsome creatures, and droids of various levels and across all Star Wars eras.... |
 | Stars and Galaxies by Michael A. Seeds With this newly revised sixth edition of STARS AND GALAXIES, author Mike Seeds' goal is to help you use astronomy to understand science--and use science to understand what we are. Fascinating and engaging, this text will help you answer two fundamental questions: What are we? How do we know? Crafting a story about astronomy, Seeds shows you how to ask questions to gradually puzzle out the... |
| © 2008 BrightSurf.com |