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Merging Galaxies Create a Binary Quasar

For Release: February 3, 2010

Carnegie Institution

NGC 1399
Credit: X-ray (NASA/CXC/SAO/P. Green et al.), Optical (Carnegie Obs./Magellan/W.Baade Telescope/J.S.Mulchaey et al.)
Press Image and Caption

Astronomers have found the first clear evidence of a binary quasar within a pair of actively merging galaxies. Quasars are the extremely bright centers of galaxies surrounding super-massive black holes, and binary quasars are pairs of quasars bound together by gravity. Binary quasars, like other quasars, are thought to be the product of galaxy mergers. Until now, however, binary quasars have not been seen in galaxies that are unambiguously in the act of merging. But images of a new binary quasar from the Carnegie Institution's Magellan telescope in Chile show two distinct galaxies with "tails" produced by tidal forces from their mutual gravitational attraction.

"This is really the first case in which you see two separate galaxies, both with quasars, that are clearly interacting," says Carnegie astronomer John Mulchaey who made observations crucial to understanding the galaxy merger.

Most, if not all, large galaxies, such as our galaxy the Milky Way, host super-massive black holes at their centers. Because galaxies regularly interact and merge, astronomers have assumed that binary super-massive black holes have been common in the Universe, especially during its early history. Black holes can only be detected as quasars when they are actively accreting matter, a process that releases vast amounts of energy. A leading theory is that galaxy mergers trigger accretion, creating quasars in both galaxies. Because most such mergers would have happened in the distant past, binary quasars and their associated galaxies are very far away and therefore difficult for most telescopes to resolve.

The binary quasar, labeled SDSS J1254+0846, was initially detected by the Sloan Digital Sky Survey, a large scale astronomical survey of galaxies and over 120,000 quasars. Further observations by Paul Green of the Harvard-Smithsonian Center for Astrophysics and colleagues* using NASA's Chandra's X-ray Observatory and telescopes at Kitt Peak National Observatory in Arizona and Palomar Observatory in California indicated that the object was likely a binary quasar in the midst of a galaxy merger. Carnegie's Mulchaey then used the 6.5 meter Baade-Magellan telescope at the Las Campanas observatory in Chile to obtain deeper images and more detailed spectroscopy of the merging galaxies.

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"Just because you see two galaxies that are close to each other in the sky doesn't mean they are merging," says Mulchaey. "But from the Magellan images we can actually see tidal tails, one from each galaxy, which suggests that the galaxies are in fact interacting and are in the process of merging."

Thomas Cox, now a fellow at the Carnegie Observatories, corroborated this conclusion using computer simulations of the merging galaxies. When Cox's model galaxies merged, they showed features remarkably similar to what Mulchaey observed in the Magellan images. "The model verifies the merger origin for this binary quasar system," he says. "It also hints that this kind of galaxy interaction is a key component of the growth of black holes and production of quasars throughout our universe."

* The authors of the paper published in the Astrophysical Journal are Paul J. Green of the Harvard-Smithsonian Center for Astrophysics, Adam D. Myers of the University of Illinois at Urbana-Champaign, Wayne A. Barkhouse of the University of North Dakota, John S. Mulchaey of the Observatories of the Carnegie Institution for Science, Vardha N. Bennert of the Department of Physics, University of California, Santa Barbara, Thomas J. Cox of the Observatories of the Carnegie Institution for Science, Thomas L. Aldcroft of the Harvard-Smithsonian Center for Astrophysics, and Joan M. Wrobel of National Radio Astronomy Observatory, Socorro, NM.

More information, including images and other multimedia, can be found at: and

Media contacts:
Alan Cutler
Carnegie Institution for Science.

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.

Visitor Comments (31)

Dear Aubrey Hogan,
Thanks for your comment. I see some discussion of "plasmoids" in peer-reviewed papers, mostly to do with solar system phenomena, though without further research I don't know if any of these correspond to "Bostick's" plasmoids and the related theories of an "electric Universe". However, any arguments that these plasmoids discount the need for black holes (or important elements of modern cosmology, including the existence of dark matter and dark energy) are well outside mainstream thinking. There are many independent lines of evidence for the existence of black holes, dark matter and dark energy. That doesn't prove that these "electric Universe" theories are wrong, it just means they're very unlikely to be right.
P. Edmonds for CXC

Posted by P. Edmonds on Tuesday, 08.31.10 @ 09:21am

The observed phenomena looks exactly like Bostick's plasmoids and is an excellent support for electric universe theory. No mystical, unobservable, unmeasurable, unfalsifiable, dark occult properties are required to explain any of it. The images are really awesome. Thank you. The explanations offered are weak. It is unfortunate that more credence is not given to other theories. When only one theory is allowed to be considered, it isn't science anymore. It is religion.

Posted by Aubrey Hogan on Thursday, 08.19.10 @ 14:13pm

What is a light year?

Posted by dg on Friday, 04.2.10 @ 18:32pm

Dear Garry,
Thanks for your question. There are many different pieces of evidence for black holes, including measurements of the mass of compact objects in binary systems:

and studying the orbits of stars near the center of our galaxy, which point to an object weighing about 4 million times the mass of the Sun. The prodigious amounts of light produced by quasars are also best explained by black holes. These don't constitute proof that black holes exist, but taken together they represent powerful evidence.

P. Edmonds for CXC

Posted by P. Edmonds on Wednesday, 03.3.10 @ 10:46am

Dear Bill,
Thanks for your comment: the evidence that Markarian 205 is directly connected to a neighboring galaxy at a very different redshift is too weak to be taken seriously. It is perfectly reasonable for two objects at different distances - but closely separated on the sky - to show regions of overlapping light. There is an overwhelming amount of evidence that redshifts accurately give distances in the cosmos.

P. Edmonds for CXC

Posted by P. Edmonds on Wednesday, 03.3.10 @ 10:44am

Dear Jake,
Thanks for your comment which we'll take into account.

P. Edmonds for CXC

Posted by P. Edmonds on Wednesday, 03.3.10 @ 10:42am

I wish there were audio to go along with your articles similar to what Dr. Tony Phillips does on Science Nasa Gov.

Posted by Jake on Tuesday, 02.16.10 @ 00:20am

Many years ago Emil Wolf showed that radio signatures that associate with quasars are produced when light passes through turbulent radio atmospheres as must happen when galaxies colide. We have known for more than a decade that Markarian 205 has a filament directly connecting the galaxy less than 200,000 light years away to a quasar that was once believed to be millions of light years beyond Markarian 205. How can you tell the difference?

Posted by Bill Tieckelmann on Monday, 02.15.10 @ 17:40pm

Why do Astronomers state as fact that black holes exist? It is still only a theory but it seems the assumption is gospel X-Rays are a electromagnetic phenomenon i e an electric current a magnetic field.

Posted by Garry Maxfield on Thursday, 02.11.10 @ 21:57pm

Very good, and it is a relevant area as our galaxy heads toward Andromeda, so we can look to see interactive relations in collision and black hole action.

Posted by Neal on Thursday, 02.11.10 @ 07:04am

Dear Sourav Maiti,
There is a quasar in each of the two galaxies that are undergoing this
P. Edmonds for CXC

Posted by P. Edmonds on Tuesday, 02.9.10 @ 14:11pm

Dear J. Madson,
Thanks for your question. There is the "Local Hot Bubble", and I see
there's a post about this on wikipedia. You can use this as a starting
point to learn more. There are bound to be many other bubbles, but they
will be hard to detect around other stars.
P. Edmonds for CXC

Posted by P. Edmonds on Tuesday, 02.9.10 @ 14:09pm

Dear Ariel
Thanks very much for the heads-up!
P. Edmonds for CXC

Posted by P. Edmonds on Tuesday, 02.9.10 @ 14:07pm

So good.

Posted by DEVI on Tuesday, 02.9.10 @ 05:00am

Thanks for posting this. It discussed very well, also it is very much informative. However, I want to know whether these two quasars are living in only one galaxy or both the two galaxies.

Posted by Sourav Maiti on Sunday, 02.7.10 @ 12:10pm

Meraviglioso (marvellous). As Oscar Wilde said. "We are all in the gutter, but some of us are looking at the stars."
Thank you for the beautiful works.

Posted by Elisabetta di Cagno on Saturday, 02.6.10 @ 15:30pm

Maybe the physics of the forming object also produces secondaries, which produces its own secondaries etc as size and energy permits.

Posted by J. Madson on Saturday, 02.6.10 @ 07:00am

I have a question. Are there bubbles aside of other stars? I understand that there is one near the solar system. Is it common? I don’t mean the heliospheric-gas interaction oblateness, just a bubble. At what size relative to the solar system? What motions? What shape? Paticles may be inside it emitting a frequency that can be read. Is there inter-action with the solar system?

Posted by J. Madson on Saturday, 02.6.10 @ 06:53am

How inspiring and interesting to see if any similar objects can be found nearer to milky way and what if any affect it may have on us.

Posted by Sid Sefton on Friday, 02.5.10 @ 15:23pm

Think of it, the light were seeing left. About the same time as the birth of our planet.
Sometimes, looking at these images, I feel I'm looking into eternity.
Sam, Galt, CA

Posted by Sam on Friday, 02.5.10 @ 13:54pm

Amazing, but did you check the SDSS J1254+0846 in Wikisky? The quasars are already there. Also, I can see a strong UV emission from Wikisky GALEX survey.

Posted by Ariel on Friday, 02.5.10 @ 10:31am

Dear Friends at Chandra,
Thanks a lot for regular & today's information with related links, help us to boost our knowledge.

Posted by ddpurohit vadodara on Friday, 02.5.10 @ 07:57am


Posted by Victor on Friday, 02.5.10 @ 07:50am

Very good. Thank you.

Posted by Roy Wolford on Friday, 02.5.10 @ 00:33am


Posted by prof nataraj k s on Thursday, 02.4.10 @ 23:43pm

I want to see an actual dead on center collision between two quasars in order to see what the result is.

Posted by dan on Thursday, 02.4.10 @ 20:06pm

There is always something new to learn and discover. Our universe is always full of surprises just waiting for us to discover them.

This is one beautiful sight to behold

Marvin L S

Posted by Marvin L. S. on Thursday, 02.4.10 @ 13:46pm


Posted by Tom Hamblin on Thursday, 02.4.10 @ 13:34pm

Ladies and Gentlemen,
For a number of years we have been hiking and playing in the immediate vicinity of the Effelsberg Germany radio-telescope. Your magic website with its intoxicating contents allow us now to visualize some of the space objects to which radio signals from Effelsberg are being sent to. We wish you good luck and continued success in capturing these magic visions.
Regards andrew herold
Hannah Jan-Philipp

Posted by andrew herold on Thursday, 02.4.10 @ 12:23pm

This has to be spectacular.
With the Telescopes and backup now available, one wonders what is the next discovery.

Posted by Mark Ballington on Thursday, 02.4.10 @ 05:44am

So impressive and a wonderful discovery.

Posted by Ümit Fuat Özyar on Thursday, 02.4.10 @ 04:44am