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 January 30, 2015

News: Taliban claims responsibility for attack on Americans at military base near airport - The Taliban claimed responsibility Jan. 30 for a shooting incident at a military base attached to Kabul’s international airport yesterday that killed three American civilian contractors and an Afghan national, saying the attacker had infiltrated the ranks of the security forces. Commission...
 
 

News Briefs January 30, 2015

Military judge weighs restrictions on Gitmo female guards A military judge is deciding whether to continue restricting the use of female guards at Guantanamo. Navy Capt. J. Kirk Waits heard closing arguments Jan. 29 at the base in Cuba during a pretrial hearing for Abd al-Hadi al-Iraqi. Waits didn’t say when he will rule. Hadi...
 
 
Air Force photograph by 1st Lt. Jake Bailey

Cope South experts exchange knowledge, techniques

Air Force photograph by 1st Lt. Jake Bailey TSgt. Sam Bishop, center left, and SSgt. Jeffrey Stephens discuss propeller maintenance with Bangladesh air force maintainers, from the 101st Special Flying Unit, during exercise Cope...
 

 

Air Force names 2-star to lead F-35 Integration Office

With the initial operating capability date of the F-35 Lightning II quickly approaching, the Air Force appointed Maj. Gen. Jeffrey Harrigian as the director of a larger Air Force F-35 Integration Office, Feb. 1. In addition to gaining new leadership, the F-35 Integration Office will also grow from a staff of four to 12 and...
 
 
boeing-ana2

Boeing announces ANA’s commitment to more jetliners

Airline continues fleet modernization with Boeing airplanes Boeing and All Nippon Airways announced Jan. 30 the airline’s intent to purchase three 787-10 Dreamliners to add additional flexibility to the airline’s 787 fleet....
 
 
Air Force photograph by Scott M. Ash

Air Force risks becoming too small to succeed under sequestration

Air Force photograph by Scott M. Ash Air Force Chief of Staff Gen. Mark A. Welsh III testifies before the Senate Armed Services Committee Jan. 28, 2015, in Washington, D.C., as Commandant of the Marine Corps Gen. Joesph F. Dunf...
 




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>