Space

September 19, 2012

NASA telescopes spy ultra-distant galaxy amidst cosmic ‘dark ages’

With the combined power of NASA’s Spitzer and Hubble space telescopes, as well as a cosmic magnification effect, astronomers have spotted what could be the most distant galaxy ever seen.

ight from the young galaxy captured by the orbiting observatories first shone when our 13.7-billion-year-old universe was just 500 million years old.

The far-off galaxy existed within an important era when the universe began to transit from the so-called cosmic dark ages. During this period, the universe went from a dark, starless expanse to a recognizable cosmos full of galaxies. The discovery of the faint, small galaxy opens a window onto the deepest, remotest epochs of cosmic history.

“This galaxy is the most distant object we have ever observed with high confidence,” said Wei Zheng, a principal research scientist in the department of physics and astronomy at Johns Hopkins University in Baltimore and lead author of a new paper appearing in Nature. “Future work involving this galaxy, as well as others like it that we hope to find, will allow us to study the universe’s earliest objects and how the dark ages ended.”

Light from the primordial galaxy traveled approximately 13.2 billion light-years before reaching NASA’s telescopes. In other words, the starlight snagged by Hubble and Spitzer left the galaxy when the universe was just 3.6 percent of its present age. Technically speaking, the galaxy has a redshift, or “z,” of 9.6. The term redshift refers to how much an object’s light has shifted into longer wavelengths as a result of the expansion of the universe. Astronomers use redshift to describe cosmic distances.

Unlike previous detections of galaxy candidates in this age range, which were only glimpsed in a single color, or waveband, this newfound galaxy has been seen in five different wavebands. As part of the Cluster Lensing And Supernova Survey with Hubble Program, the Hubble Space Telescope registered the newly described, far-flung galaxy in four visible and infrared wavelength bands. Spitzer measured it in a fifth, longer-wavelength infrared band, placing the discovery on firmer ground.

Objects at these extreme distances are mostly beyond the detection sensitivity of today’s largest telescopes. To catch sight of these early, distant galaxies, astronomers rely on gravitational lensing. In this phenomenon, predicted by Albert Einstein a century ago, the gravity of foreground objects warps and magnifies the light from background objects. A massive galaxy cluster situated between our galaxy and the newfound galaxy magnified the newfound galaxy’s light, brightening the remote object some 15 times and bringing it into view.

Based on the Hubble and Spitzer observations, astronomers think the distant galaxy was less than 200 million years old when it was viewed. It also is small and compact, containing only about 1 percent of the Milky Way’s mass. According to leading cosmological theories, the first galaxies indeed should have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.

These first galaxies likely played the dominant role in the epoch of reionization, the event that signaled the demise of the universe’s dark ages. This epoch began about 400,000 years after the Big Bang when neutral hydrogen gas formed from cooling particles. The first luminous stars and their host galaxies emerged a few hundred million years later. The energy released by these earliest galaxies is thought to have caused the neutral hydrogen strewn throughout the universe to ionize, or lose an electron, a state that the gas has remained in since that time.

“In essence, during the epoch of reionization, the lights came on in the universe,” said paper co-author Leonidas Moustakas, a research scientist at NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif.

Astronomers plan to study the rise of the first stars and galaxies and the epoch of reionization with the successor to both Hubble and Spitzer, NASA’s James Webb Telescope, which is scheduled for launch in 2018. The newly described distant galaxy likely will be a prime target.

 




All of this week's top headlines to your email every Friday.


 
 

 

Headlines September 19, 2014

News: McKeon on broader military authorization: Anything can ‘fail or pass’ - Rep. Howard “Buck” McKeon, R-Calif., chairman of the House Armed Services Committee, said if Congress returns after the midterm elections to weigh a broader military authorization for the battle against Islamic State, it might not pass. Defense contractor gets 7 years for giving secrets...
 
 

News Briefs September 19, 2014

U.S. military deaths in Afghanistan at 2,203 As of Sept. 16, 2014, at least 2,203 members of the U.S. military had died in Afghanistan as a result of the U.S.-led invasion of Afghanistan in late 2001, according to an Associated Press count. At least 1,823 military service members have died in Afghanistan as a result...
 
 

Pratt & Whitney, U.S. Air Force complete qualification for F135 engine testing

Pratt & Whitney, a United Technologies Corp. , together with its U.S. Air Force partner at the F135 Heavy Maintenance Center at Tinker Air Force Base, Okla., celebrated another significant milestone qualification for F135 engine testing at the Oklahoma City Air Logistics Complex. OC-ALC which in addition to engine testing is also qualified to perform...
 

 
Navy photograph

Triton has first cross-country flight from Palmdale

Northrop Grumman photograph The MQ-4C Triton Unmanned Aircraft System takes off from Northrop Grummanís Palmdale, Calif., facility Sept. 17 for its first cross-country flight to Naval Air Station Patuxent, River, Md. PALMDALE,...
 
 
Air Force photograph by Michael J. Pausic

Future of NATO: Adapting to a new security environment

Air Force photograph by Michael J. Pausic Gen. Phillip Breedlove informs the assembled crowd about the results of the recent NATO Summit and the areas of instability that affect Europe that have regional implications. Seated in...
 
 
Air Force photograph by Scott M. Ash

AFRL commander describes Air Force’s technology vision

Air Force photograph by Scott M. Ash Maj. Gen. Thomas Masiello takes a question from an audience member after discussing Air Force Research Laboratory breakthrough technologies during the 2014 Air Force Association’s Air ...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>