Galaxy Cores to Crash in a Few Million Years

March 16, 2009
This image of a pair of colliding galaxies called NGC 6240 shows them in a rare, short-lived phase of their evolution just before they merge into a single, larger galaxy.

(PhysOrg.com) -- A new image from NASA's Spitzer Space Telescope offers a rare view of an imminent collision between the cores of two merging galaxies, each powered by a black hole with millions of times the mass of the sun.

The galactic cores are in a single, tangled galaxy called NGC 6240, located 400-million light years away in the constellation Ophiuchus. Millions of years ago, each core was the dense center of its own galaxy before the two collided and ripped each other apart. Now, these cores are approaching each other at tremendous speeds and preparing for the final cataclysmic collision. They will crash into each other in a few million years, a relatively short period on a galactic timescale.

The spectacular image combines from NASA's and from Spitzer. It catches the two galaxies during a rare, short-lived phase of their evolution, when both cores of the interacting galaxies are still visible but closing in on each other fast.

"One of the most exciting things about the image is that this object is unique," said Stephanie Bush of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., lead author of a new paper describing the observation in an upcoming issue of the Astrophysical Journal. "Merging is a quick process, especially when you get to the train wreck that is happening. There just aren't many at this stage in the nearby universe."

NGC 6240 is already putting out huge amounts of infrared light, an indication that a burst of star formation is underway. The extra is common in interacting galaxies; as the two galaxies interact, dust and gas swept up by the collision form a burst of new stars that give off infrared light. Such galaxies are called luminous infrared galaxies. Spitzer's can image the extra heat from newly formed stars, even though their visible light is obscured by thick dust clouds around them.

The blob-like shape of the galaxy is due to the sustained violence of the collision. Streams of millions of stars are being ripped off the galaxy, forming wispy "tidal tails" that lead off NGC 6240 in several directions. But things are about to get even more violent as the main event approaches and the two galactic cores meld into one.

In the center of NGC 6240, the two black holes in the cores will whip up a frenzy of radiation as they careen towards one another head-on, likely transforming the galaxy into a monster known as an ultra-luminous infrared galaxy, thousands of times as bright in infrared as our Milky Way.

Another fascinating aspect of this rare object is that no two galactic mergers are the same. "Not only are there few objects at this stage, but each object is unique because it came from different progenitor galaxies," said Bush. "These observations give us another layer of information about this galaxy, and galactic mergers in general."

Infrared light taken by Spitzer's infrared array camera at 3.6 and 8.8 microns (red) shows cold dust and radiation from star formation; visible light from Hubble (green and blue) shows hot gas and stars.

Other authors of this paper include Zhong Wang, Margarita Karovska and Giovanni Fazio, all of the Harvard-Smithsonian Center for Astrophysics.

Provided by JPL/NASA (news : web)

Explore further: Spitzer Witnessed Galactic Collision

Related Stories

Spitzer Witnessed Galactic Collision

September 10, 2004

NASA's Spitzer Space Telescope has set its infrared sight on a major galactic collision and witnessed not death, but a teeming nest of life. The colliding galaxies, called the Antennae galaxies, are in the process of merging ...

Hubble Eyes Star Birth in the Extreme

June 13, 2006

Staring into the crowded, dusty core of two merging galaxies, NASA's Hubble Space Telescope has uncovered a region where star formation has gone wild.

Hubble sees the graceful dance of 2 interacting galaxies

October 30, 2007

A pair of galaxies, known collectively as Arp 87, is one of hundreds of interacting and merging galaxies known in our nearby Universe. Arp 87 was originally discovered and catalogued by astronomer Halton Arp in the 1970s. ...

Hats Off to Space Day From NASA's Spitzer Space Telescope

May 5, 2005

NASA salutes Space Day, observed this year on May 5, with a new dramatic image of the Sombrero galaxy. Space Day, held the first Thursday each May, is designed to inspire the next generation of explorers. The galaxy, called ...

Galaxies Don Mask of Stars in New Spitzer Image

April 26, 2006

A pair of dancing galaxies appears dressed for a cosmic masquerade in a new image from NASA's Spitzer Space Telescope. The infrared picture shows what looks like two icy blue eyes staring through an elaborate, swirling red ...

Hubble's view of barred spiral galaxy NGC 1672

April 3, 2007

NGC 1672, visible from the Southern Hemisphere, is seen almost face on and shows regions of intense star formation. The greatest concentrations of star formation are found in the so-called starburst regions near the ends ...

Recommended for you

Solar-powered rover approaching 5,000th Martian dawn

February 16, 2018

The sun will rise on NASA's solar-powered Mars rover Opportunity for the 5,000th time on Saturday, sending rays of energy to a golf-cart-size robotic field geologist that continues to provide revelations about the Red Planet.

Supermassive black holes are outgrowing their galaxies

February 15, 2018

The growth of the biggest black holes in the Universe is outrunning the rate of formation of stars in the galaxies they inhabit, according to two new studies using data from NASA's Chandra X-ray Observatory and other telescopes ...

Hubble sees Neptune's mysterious shrinking storm

February 15, 2018

Three billion miles away on the farthest known major planet in our solar system, an ominous, dark storm - once big enough to stretch across the Atlantic Ocean from Boston to Portugal - is shrinking out of existence as seen ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

dirk_bruere
not rated yet Mar 16, 2009
Sounds pretty bleak for any life in those galaxies.
snwboardn
not rated yet Mar 16, 2009
Pretty crazy to think that it already happened 399 Million years ago.
Honor
not rated yet Mar 17, 2009
have to wait for the gravity wave

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.