Merging galaxies create a binary quasar (w/ Video)

Feb 03, 2010
This optical image of SDSS J1254+0846 obtained May 22, 2009, on the IMACS camera at the Magellan/Baade telescope at Las Campanas Observatory in Chile shows the two bright quasar nuclei as well as the tidal arms of the host galaxy merger. Scale bar is 10 arcseconds. Credit: Credit: Carnegie Institution

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 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 .

"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.

This video is not supported by your browser at this time.
This movie of a numerical simulation shows a galaxy merger similar to SDSS J1254+0846 over a time span of 3.6 billion years (Gyr). At 2.33 Gyr the two model galaxies and their quasars resemble the image observed with the Magellan telescope. Credit: T.J. Cox/Carnegie Institution

Most, if not all, large galaxies, such as our galaxy the Milky Way, host super-massive 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 of 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 , 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.

This optical image of SDSS J1254+0846 obtained May 22, 2009, on the IMACS camera at the Magellan/Baade telescope at Las Campanas Observatory in Chile shows the two bright quasar nuclei as well as the tidal arms of the host galaxy merger. Scale bar is 10 arcseconds. Credit: Carnegie Institution

"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."

Credits: X-ray: NASA/CXC/SAO/P. Green et al. Optical: Carnegie Obs./Magellan/W. Baade Telescope/J.S. Mulchaey et al.


Explore further: How baryon acoustic oscillation reveals the expansion of the universe

More information: The research paper has been published in the Astrophysical Journal. Link to paper: stacks.iop.org/0004-637X/710/1578

Provided by Carnegie Institution

4.6 /5 (24 votes)

Related Stories

Galaxy 'hunting' made easy

Sep 14, 2007

Astronomers using ESO's Very Large Telescope have discovered in a single pass about a dozen otherwise invisible galaxies halfway across the Universe. The discovery, based on a technique that exploits a first-class ...

Chandra finds evidence for quasar ignition

Mar 23, 2006

New data from NASA's Chandra X-ray Observatory may provide clues to how quasars "turn on." Since the discovery of quasars over 40 years ago, astronomers have been trying to understand the conditions surrounding ...

Astronomers discover a trio of quasars

Jan 08, 2007

Using ESO's Very Large Telescope and the W.M. Keck Observatory, astronomers at the Ecole Polytechnique Fédérale de Lausanne in Switzerland and the California Institute of Technology, USA, have discovered ...

Recommended for you

The Great Cold Spot in the cosmic microwave background

51 minutes ago

The cosmic microwave background (CMB) is the thermal afterglow of the primordial fireball we call the big bang. One of the striking features of the CMB is how remarkably uniform it is. Still, there are some ...

Mystery of rare five-hour space explosion explained

Sep 17, 2014

Next week in St. Petersburg, Russia, scientists on an international team that includes Penn State University astronomers will present a paper that provides a simple explanation for mysterious ultra-long gamma-ray ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

yyz
5 / 5 (1) Feb 03, 2010
A free eprint of the paper at: http://arxiv.org/...38v2.pdf . Truly awesome looking object.
jamesrm
5 / 5 (1) Feb 03, 2010
"Most, if not all, large galaxies, such as our galaxy the Milky Way, host super-massive black holes at their centers."

Seems their is Zero room for these doubt?
frajo
3.7 / 5 (3) Feb 04, 2010
Seems their is Zero room for these doubt?
You could create room for doubt. With a sound argument.
Skeptic_Heretic
5 / 5 (1) Feb 05, 2010
Quasars are one of the more interesting things in the Universe. Is it reasonable to assume that all Quasars are potentially the product of merged or merging galaxies? Just imagine how much dust and other matter is tossed into the galactic cores of merging galaxies.
Adriab
not rated yet Feb 05, 2010
Crazy idea:
Imagine a solar-system based off a red dwarf, with terrestrial planets (at least one or two). Now place it at some distance from an AGN such that the amount of energy coming from the AGN could create a "habitable zone" for the entire planetary system.

I know it is a wild conjecture, but still I enjoy the imagination exercise.