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.


 
 

 
nasa-commercial-crew

Commercial Crew milestones met; partners on track for 2017 missions

NASA has taken another step toward returning America’s ability to launch crew missions to the International Space Station from the United States in 2017. The Commercial Crew Program ordered its first crew rotation mission fro...
 
 
boeing-space

Boeing awarded first-ever commercial human spaceflight mission

NASA issued a task order as part of Boeing’s $4.2 billion Commercial Crew Transportation Capability contract recently to include the company’s first-ever service flight to the International Space Station. The award ...
 
 
Photograph courtesy of NASA/JPL-Caltech

NASA’s Europa mission begins with selection of science instruments

Photograph courtesy of NASA/JPL-Caltech Bizarre features on Europa’s icy surface suggest a warm interior. This view of the surface of Jupiter’s moon Europa was obtained by NASA’s Galileo mission, and shows a color...
 

 
Photograph courtesy of NASA/JPL-Caltech/Lockheed Martin

NASA begins testing Mars lander in preparation for next mission to Red Planet

Photograph courtesy of NASA/JPL-Caltech/Lockheed Martin Engineers and technicians at Lockheed Martin Space Systems, Denver, run a test of deploying the solar arrays on NASA’s InSight lander. Photo taken April 30, 2015. Te...
 
 
Image courtesy of NASA/JPL-Caltech

NASA’s WISE spacecraft discovers most luminous galaxy in universe

Image courtesy of NASA/JPL-Caltech This artist’s concept depicts the current record holder for the most luminous galaxy in the universe. The galaxy, WISE J224607.57-052635.0, is erupting with light equal to more than 300 ...
 
 

Air Force launches hush-hush mini-shuttle into space

A mysterious space plane rocketed into orbit May 20, carrying no crew but a full load of technology experiments. The Air Force launched its unmanned mini-shuttle late morning, May 20. An Atlas V rocket lifted it up and out over the Atlantic. This is the fourth flight for the military research program, which is shrouded...
 




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>