http://abcnews.go.com/Technology/wireStory?id=11927711

Astronomers Find Oldest Galaxy Yet

October 20, 2010

WASHINGTON (Reuters) - Astronomers have spotted the oldest galaxy ever seen, one born just 600 million years after the Big Bang.

Their report, published in the journal Nature on Wednesday, confirms that the distant smudge first spotted by the orbiting Hubble Space Telescope is the farthest and thus oldest object ever imaged.

The galaxy has the unglamorous name of UDFy-38135539, the team of European researchers said.

"Here we report the detection of ... photons emitted less than 600 million years after the Big Bang," they wrote.

Light travels at a speed of 186,000 miles a second, or about 6 trillion miles (10 trillion km) a year. Astronomers can use light-speed as a kind of time machine, and seeing light emitted from objects very far away shows them as they were in the past.

In this case, the galaxy's light first started traveling 13 billion years ago, right after the Big Bang.

The distance is measured using what is called red shift, a kind of Doppler effect of light. Just as a train's whistle seems to change in pitch as the train approaches and passes, light's color also shifts.

This galaxy has a red shift of 8.55, making it the farthest and oldest ever seen.

At this time in the early universe, a haze of hydrogen gas was everywhere, but radiation from primeval galaxies was causing a process called ionization that changed the nature of the hydrogen.

The report "represents a fundamental leap forward in observational cosmology", Michele Trenti of the University of Colorado, Boulder, wrote in a commentary.

(Reporting by Maggie Fox, Editing by Julie Steenhuysen and Jerry Norton)

http://www.indyposted.com/118735/astonomers-find-oldest-galaxy-yet/

Astonomers Find Oldest Galaxy Yet
Oct 20 2010 Posted in Science by Dan Evon

Read The Full Story: Astonomers Find Oldest Galaxy Yet – Indyposted

Oldest Galaxy

Astronomers have found the oldest galaxy they have ever seen. The Galaxy is believed to be 13.1 billion years old, which makes it the oldest thing ever discovered in space.

According to the Associated Press, the galaxy was hidden in a Hubble Telescope photo released early this year. It’s just a small smudge of light in the photo, but European astronomers have determined that it is a galaxy from more than 13 billion years ago.

In fact, the galaxy is so old that it probably doesn’t even exist in its earlier form anymore.

Richard Ellis, an astronomy professor from the California Institute of Technology said:

“We’re looking at the universe when it was a 20th of its current age. In human terms, we’re looking at a 4-year-old boy in the life span of an adult.”

The new galaxy doesn’t have a name, but astronomers refer to it as the high red-shift blob.

http://www.latimes.com/news/science/la-sci-distant-galaxy-20101021,0,6515755.sto...

Far-off galaxy is found

Born just 500 million years after the Big Bang, the galaxy could help explain the 'reionization' of the universe.

By Eryn Brown, Los Angeles Times

October 21, 2010

Scientists have found the most distant space object yet observed, a galaxy born just 500 million years after the Big Bang.

The record-breaking discovery, reported Wednesday in the journal Nature, may aid exploration of a crucial period in the early history of the cosmos — a time when light from the earliest stars broke up the fog of hydrogen gas that shrouded the universe shortly after the Big Bang. That process created the "reionized" universe that exists today, scientists think.

"This is one of the most fundamental problems in astronomy — how the universe ionized," said the study's lead author, astronomer Matthew Lehnert of the Observatoire de Paris in France.

Lehnert said that though astronomers know reionization occurred, they don't understand how, because they haven't been able to observe the process underway. "That's why [seeing this object] matters," he said.

The Hubble Space Telescope first spotted the galaxy, named UDFy-38135539, after a camera that permitted clearer images of distant objects was installed on the telescope in May 2009. In October of that year, scientists began analyzing photos of a far-off portion of the sky known as the Hubble Ultra Deep Field.

They identified several faint "blobs" that might have been distant galaxies, Lehnert said. To confirm, astronomers needed to analyze the blobs' light with a spectrograph — a device that could determine whether the light resembled that typically seen escaping far-off stars.

The team wasn't sure the objects Hubble uncovered would be bright enough to analyze this way. Still, Lehnert secured 16 hours of time — considered generous — to observe UDFy-38135539 with the European Southern Observatory's Very Large Telescope and the SINFONI spectrograph in Chile.

Crunching through the data over the course of two months, Lehnert and his colleagues determined with 99.99% certainty that the object's light did appear to be coming from a distant galaxy, according to the Nature study.

The spectrograph also allowed scientists to pin down the galaxy's so-called redshift, a measure of how fast the galaxy and Earth were moving away from each other due to the expansion of the universe. The larger the redshift, the more distant — and more ancient — the observation.

UDFy-38135539 had a redshift of 8.55 — meaning that light escaping it was emitted more than 13 billion years ago. The farthest galaxy previously detected had a redshift of 6.96. Its light started the trip toward Earth about 150 million years later than that of UDFy-38135539.

"It's remarkable that in such a short time, well-developed galaxies already existed" in the universe, said Michele Trenti, an astrophysicist at the Center for Astrophysics and Space Astronomy of the University of Colorado in Boulder.

Trenti, who wrote an editorial accompanying the Nature paper, said it was likely there were more galaxies lurking at these great distances.

About one-tenth of the diameter of the Milky Way, and composed of approximately one billion stars, UDFy-38135539 wouldn't emit enough light on its own to ionize the hydrogen gas that surrounded it, the Nature article reported. Unless there were more galaxies around it to help break down the hydrogen fog, the galaxy's light probably could never have reached Earth.

Because UDFy-38135539's glow is so faint, some scientists said they were skeptical of the results.

"The question of whether this is definitively the oldest is uncertain," said Caltech astronomer Richard Ellis, who is coauthor of a forthcoming review in Nature about the reionization of the universe. "This is an ambitious and difficult measurement. People have been wrong before."

But Ellis said the research remained "impressive," and that it "demonstrates that it's feasible to prove that these [galaxies] exist at long distances." By viewing more distant galaxies, astronomers will figure out what happened in the universe's early years, he said.

"We're about to find out about one of the most interesting periods of the universe, about which not much is known," he said. "It's the last frontier, and we're on the brink of observationally nailing it down."

http://www.nytimes.com/aponline/2010/10/20/science/space/AP-US-SCI-Oldest-Galaxy...

The New York Times/AP

Astronomers Say They've Found Oldest Galaxy So Far

By THE ASSOCIATED PRESS
Published: October 20, 2010

Filed at 5:30 p.m. ET

NASA, via Associated Press

Photo: Part of a Hubble Space Telescope image that shows a galaxy European astronomers say is the oldest observed to date.

WASHINGTON (AP) — Astronomers believe they've found the oldest thing they've ever seen in the universe: It's a galaxy far, far away from a time long, long ago.

Hidden in a Hubble Space Telescope photo released earlier this year is a small smudge of light that European astronomers now calculate is a galaxy from 13.1 billion years ago. That's a time when the universe was very young, just shy of 600 million years old. That would make it the earliest and most distant galaxy seen so far.

By now the galaxy is so ancient it probably doesn't exist in its earlier form and has already merged into bigger neighbors, said Matthew Lehnert of the Paris Observatory, lead author of the study published online Wednesday in the journal Nature.

"We're looking at the universe when it was a 20th of its current age," said California Institute of Technology astronomy professor Richard Ellis, who wasn't part of the discovery team. "In human terms, we're looking at a 4-year-old boy in the life span of an adult."

While Ellis finds the basis for the study "pretty good," there have been other claims about the age of distant space objects that have not held up to scrutiny. And some experts have questions about this one. But even the skeptics praised the study as important and interesting.

The European astronomers calculated the age after 16 hours of observations from a telescope in Chile that looked at light signatures of cooling hydrogen gas.

Earlier this year, astronomers had made a general estimate of 600 to 800 million years after the Big Bang for the most distant fuzzy points of light in the Hubble photograph, which was presented at an astronomy meeting back in January.

In the new study, researchers focused on a single galaxy in their analysis of hydrogen's light signature, further pinpointing the age. Garth Illingworth of the University of California, Santa Cruz, who was the scientist behind the Hubble image, said it provides confirmation for the age using a different method, something he called amazing "for such faint objects."

The new galaxy doesn't have a name — just a series of letters and numbers. So Lehnert said he and colleagues have called it "the high red-shift blob. "Because it takes so long for the light to travel such a vast time and distance, astronomers are seeing what the galaxy looked like 13.1 billion years ago at a time when it was quite young — maybe even as young as 100 million years old — Lehnert said. It has very little of the carbon or metal that we see in more mature stars and is full of young, blue massive stars, he said.

What's most interesting to astronomers is that this finding fits with theories about when the first stars and galaxies were born. This galaxy would have formed not too soon after them.

"We're looking almost to the edge, almost within 100 million years of seeing the very first objects," Ellis said. "One hundred million years to a human seems an awful long time, but in astronomical time periods, that's nothing compared to the life of the stars."

http://news.sciencemag.org/sciencenow/2010/10/galaxy-is-most-distant-object-ev.h...

Galaxy Is Most Distant Object Ever Seen
by Yudhijit Bhattacharjee on 20 October 2010, 1:27 PM
sn-galaxies.jpg

Photo: Behind the veil. One of these remote objects imaged by Hubble last year is a galaxy from 13.1 billion years ago, when the universe was being reionized. (Inset) A simulation of the reionizing process, which cleared away the fog of hydrogen around the galaxy.
Credit: NASA/ESA/G.Illingworth/ the HUDF09 Team; (inset) ESO

Astronomers have measured the distance to the farthest cosmic object known to humankind: a galaxy that lies 13.1 billion light-years away. Imaged last year by Hubble's new Wide Field Camera 3, the galaxy takes researchers back to a mere 600 million years after the big bang. Not only does it smash the previous record for most distant object—a gamma-ray burst that went off 13 billion years ago—but it is also the first object to be detected from an era when the universe was just emerging from an opaque veil of hydrogen gas.

A few hundred thousand years after the big bang, protons and electrons started joining together to form hydrogen. About 150 million years later, the first stars and galaxies began to form, but they remained enveloped in a fog of hydrogen gas which absorbed the light emitted by the earliest stars. Over the next several hundred million years—until the universe was 800 hundred million years old—the radiation from these early stars and galaxies split the surrounding hydrogen into protons and electrons, thus clearing away the fog and making the universe transparent. Researchers call this period the epoch of reionization.

The sighting of the remote galaxy—named UDFy-38135539—supports this theoretical timeline, showing that reionization was well under way 600 million years after the big bang. That's because if the hydrogen "fog" in front of the galaxy had not lifted by then, light from the galaxy would not have reached Earth. The galaxy itself contributed to this reionizing process that shredded the veil obscuring it, although its radiation alone would not have been enough to do the job. "There must be other galaxies, probably fainter and less massive nearby companions of UDFy-38135539, which also helped make the space around the galaxy transparent," says one of the paper's authors, Mark Swinbank of the University of Durham in the United Kingdom. "Without this additional help, the light from the galaxy, no matter how brilliant, would have been trapped in the surrounding hydrogen fog."

The galaxy was one of several faint objects identified as potentially remote in pictures taken last year by Hubble. To measure the distance to the galaxy, lead author Matthew Lehnert of the Paris Observatory, Nicole Nesvadba of the University of Paris, and their colleagues took a spectrum of the object using a spectrograph mounted on the European Southern Observatory's Very Large Telescope in Chile. By analyzing the spectrum, the researchers determined that the galaxy had a red shift of 8.55, corresponding to a distance of 13.1 billion light-years, they report online today in Nature.

Garth Illingworth, an astronomer at the University of California, Santa Cruz, and the leader of a team that identified this and other remote objects in the Hubble images last year, calls the finding a "very interesting result." However, he says he is a "little skeptical" about whether the spectral analysis is accurate because the object in the Hubble image "is really faint."

Avi Loeb, an astrophysicist at Harvard University, has a similar concern, although he too is excited by the find. "The validity of this discovery hangs on whether the authors have correctly identified the signal line and were not misguided by a contaminating line instead," he says, adding that observing such galaxies will become easier when the next-generation James Webb Space Telescope is launched in 2014.