Featured Research

from universities, journals, and other organizations

Galaxies Collide And Binary Black Holes Result According To Rutgers Astronomers

Date:
June 6, 2000
Source:
Rutgers, The State University Of New Jersey
Summary:
Rutgers astronomers have used large-scale computer simulations to generate compelling evidence for the the existence of binary supermassive black holes at the centers of merged galaxies. The findings were presented Monday, June 5 at the American Astronomical Society meeting in Rochester, N.Y.

NEW BRUNSWICK/PISCATAWAY, N.J. -- Astronomers from Rutgers are providing compelling evidence that suggests supermassive black holes may occur in pairs at the centers of many galaxies. A number of observations over the last three decades have hinted at the existence of such black hole binaries although the arguments have never been persuasive.

David R. Merritt, professor of physics at Rutgers, is presenting the results of large-scale computer simulations of the merger of two galaxies that support the binary black hole model. The theoretical studies, described today at the American Astronomical Society meeting in Rochester, N.Y., were a joint effort involving Merritt, postdoctoral associate Fidel Cruz and graduate student Milos Milosavljevic, all of Rutgers.

Most galaxies are observed to have supermassive black holes at their centers, a feature acknowledged to have been present since shortly after the Big Bang, the gigantic explosion that signaled the beginning of the universe. Furthermore, most large galaxies are known to have formed by the repeated mergers of smaller galaxies, a process still ongoing today but at a slower rate. The question, then, is what becomes of the black holes at the centers of a pair of galaxies as the galactic merger occurs?

"A majority of astrophysicists had previously assumed that the two black holes would rapidly coalesce following a galaxy merger," said Merritt. "Our work suggests that the black holes do fall rapidly to the center of the resulting merged galaxy, but then form a binary system that persists over time with some degree of stability. The black holes orbit about their common center of mass."

According to the results of the computer simulation studies, this binary system then gradually shrinks, as the two black holes interact gravitationally with passing stars. In effect, the black holes experience a frictional force from the stars, causing them to lose energy and come closer together. In the process, the black holes eject stars at high velocities from the center of the galaxy.

The Rutgers astronomers found that this ejection process is so efficient that the black hole pair soon finds itself isolated at the center of the galaxy, having scoured the galactic nucleus clean of stars. Once this happens, there are no longer any stars left to interact with the black holes, and their orbital decay comes to a stop. The two black holes then remain in orbit about each other with a separation of roughly one parsec, or three light-years, that remains nearly fixed for billions of years.

"Our work should motivate renewed efforts to either confirm or rule out the binary black hole model," said Merritt. He noted that the predicted one-parsec separation of the two black holes in a binary system -- while enormous in everyday terms -- is nevertheless small enough to be difficult to observe in all but the nearest galaxies. "In most galaxies, the black hole binary would appear as a single massive object. Only very high-resolution techniques, such as radio interferometry (using the combined signal from many smaller single-dish radio telescopes to electronically simulate the effect of a very large dish), have the potential to directly observe a black hole binary," he said.

While advocating the binary black hole model, Merritt does not rule out other dynamic hypotheses. "In some galaxies, the black hole binary might be induced to shrink more rapidly by the presence of large amounts of gas or some other disturbance," he said. "If the black holes approached each other very closely, it could result in an enormous burst of energy as the two supermassive black holes coalesced violently into one even more massive black hole."

But in many galaxies, the new study suggests, this dramatic coalescence might never take place. Merritt pointed out one interesting consequence of the persistence of black hole binaries: If a third galaxy should happen to merge with the first two before their black holes had coalesced, a black hole would be introduced into a nucleus that already contained two black holes. The resulting violent interaction between the three black holes would almost certainly end with the complete ejection of one or more of the black holes from the galaxy's center. In this way, "rogue" black holes might be produced that travel, undetected, between the galaxies.

EDITOR'S NOTE: For additional information, contact Dr. David Merritt while in Rochester at the Four Points Sheraton Hotel, (716) 546-6400; later at Rutgers,(732) 445-5742; at home, (732) 249-3942; by e-mail, or see http://www.physics.rutgers.edu/~merritt


Story Source:

The above story is based on materials provided by Rutgers, The State University Of New Jersey. Note: Materials may be edited for content and length.


Cite This Page:

Rutgers, The State University Of New Jersey. "Galaxies Collide And Binary Black Holes Result According To Rutgers Astronomers." ScienceDaily. ScienceDaily, 6 June 2000. <www.sciencedaily.com/releases/2000/06/000605153643.htm>.
Rutgers, The State University Of New Jersey. (2000, June 6). Galaxies Collide And Binary Black Holes Result According To Rutgers Astronomers. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2000/06/000605153643.htm
Rutgers, The State University Of New Jersey. "Galaxies Collide And Binary Black Holes Result According To Rutgers Astronomers." ScienceDaily. www.sciencedaily.com/releases/2000/06/000605153643.htm (accessed September 17, 2014).

Share This



More Space & Time News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boeing, SpaceX to Send Astronauts to Space Station

Boeing, SpaceX to Send Astronauts to Space Station

AFP (Sep. 17, 2014) — NASA selected Boeing and SpaceX on Tuesday to build America's next spacecraft to carry astronauts to the International Space Station (ISS) by 2017, opening the way to a new chapter in human spaceflight. Duration: 01:13 Video provided by AFP
Powered by NewsLook.com
East Coast Treated To Rare Meteor Sighting

East Coast Treated To Rare Meteor Sighting

Newsy (Sep. 16, 2014) — Numerous residents along the East Coast reported seeing a bright meteor flash through the sky Sunday night. Video provided by Newsy
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) — Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
NASA Picks Boeing and SpaceX to Ferry Astronauts

NASA Picks Boeing and SpaceX to Ferry Astronauts

AP (Sep. 16, 2014) — NASA is a giant step closer to launching Americans again from U.S. soil. It has announced it has picked Boeing and SpaceX to transport astronauts to the International Space Station in the next few years. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins