Space

May 22, 2013

Herschel Space Observatory finds mega merger of galaxies

A massive and rare merging of two galaxies has been spotted in images taken by the Herschel space observatory, a European Space Agency mission with important NASA participation.

Follow-up studies by several telescopes on the ground and in space, including NASA’s Hubble Space Telescope and Spitzer Space Telescope, tell a tale of two faraway galaxies intertwined and furiously making stars. Eventually, the duo will settle down to form one super-giant elliptical galaxy.

The findings help explain a mystery in astronomy. Back when our universe was 3 billion to 4 billion years old, it was populated with large reddish elliptical-shaped galaxies made up of old stars. Scientists have wondered whether those galaxies built up slowly over time through the acquisitions of smaller galaxies, or formed more rapidly through powerful collisions between two large galaxies.

The new findings suggest massive mergers are responsible for the giant elliptical galaxies.

“We’re looking at a younger phase in the life of these galaxies – an adolescent burst of activity that won’t last very long,” said Hai Fu of the University of California at Irvine, who is lead author of a new study describing the results. The study is published in the May 22 online issue of Nature.

“These merging galaxies are bursting with new stars and completely hidden by dust,” said co-author Asantha Cooray, also of the University of California at Irvine. “Without Herschel’s far-infrared detectors, we wouldn’t have been able to see through the dust to the action taking place behind.”

Herschel, which operated for almost four years, was designed to see the longest-wavelength infrared light. As expected, it recently ran out of the liquid coolant needed to chill its delicate infrared instruments. While its mission in space is over, astronomers still are scrutinizing the data, and further discoveries are expected.

In the new study, Herschel was used to spot the colliding galaxies, called HXMM01, located about 11 billion light-years from Earth, during a time when our universe was about 3 billion years old. At first, astronomers thought the two galaxies were just warped, mirror images of one galaxy. Such lensed galaxies are fairly common in astronomy and occur when the gravity from a foreground galaxy bends the light from a more distant object.
After a thorough investigation, the team realized they were actually looking at a massive galaxy merger.

Follow-up characterization revealed the duo is churning out the equivalent of 2,000 stars a year. By comparison, our Milky Way hatches about two to three stars a year. The total number of stars in both colliding galaxies averages out to about 400 billion.

Mergers are fairly common in the cosmos, but this particular event is more unusual because of the prolific amounts of gas and star formation, and the sheer size of the merger at such a distant epoch.

The results go against the more popular model explaining how the biggest galaxies arise: through minor acquisitions of small galaxies. Instead, mega smash-ups may be doing the job.

NASA’s Herschel Project Office is based at the agency’s Jet Propulsion Laboratory in Pasadena, Calif., which contributed mission-enabling technology for two of Herschel’s three science instruments.




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


 
 

 
Image courtesy of NASA Ames/JPL-Caltech/T Pyle

NASA’s Kepler reborn, makes first exoplanet find of new mission

Image courtesy of NASA Ames/JPL-Caltech/T Pyle The artistic concept shows NASA’s planet-hunting Kepler spacecraft operating in a new mission profile called K2. Using publicly available data, astronomers have confirmed K2&...
 
 
NASA illustration

NASA, planetary scientists find meteoritic evidence of Mars water reservoir

This illustration depicts Martian water reservoirs. Recent research provides evidence for the existence of a third reservoir that is intermediate in isotopic composition between the Red Planetís mantle and its current atmosphe...
 
 
Lockheed Martin photograph

Lockheed Martin-built MUOS-3 satellite encapsulated in launch vehicle fairing

Lockheed Martin photograph The U.S. Navy’s Mobile User Objective System-3 satellite (above) is encapsulated in its payload fairings for a scheduled Jan. 20, 2015 launch aboard a United Launch Alliance Atlas V rocket. MUOS ope...
 

 
NASA photograph

NASA’s Orion arrives back at Kennedy

NASA photograph NASA’s Orion spacecraft returned to the agency’s Kennedy Space Center in Florida Dec. 18, 2014. The spacecraft flew to an altitude of 3,600 miles in space during a Dec. 5 flight test designed to stre...
 
 

NASA launches new Micro-g NExT for undergraduates

NASA is offering undergraduate students an opportunity to participate in a new microgravity activity called Micro-g Neutral Buoyancy Experiment Design Teams. The deadline for proposals is Jan. 28, 2015. Micro-g NExT challenges students to work in teams to design and build prototypes of spacewalking tools to be used by astronauts for spacewalk training in the...
 
 
launch1

Storm fails to quench liftoff of secret reconnaissance satellite

The fiery launch of an Atlas V (541), among the most powerful of the venerable Atlas family, briefly dispelled the gloom over Californiaís Central Coast on the evening of Dec. 12. A team of personnel from United Launch Allianc...
 




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>