 |
|
RIT study predicts how fast a black hole can be booted from a galaxy
May 31, 2007Scientists say spin velocity determines the size and direction of the 'kick'
Scientists have discovered for the first time just how fast a supermassive black hole can be thrown from a galaxy when it merges with another black hole. The crucial factor in producing large "kicks" turns out to be the spin that the black holes carry prior to the merger.
Manuela Campanelli and her team at Rochester Institute of Technology derived a formula based on detailed computer simulations that for the first time predicts the size and direction of the kick, or radiation recoil, that follows the merger of two black holes. Their findings will be published in an upcoming issue of Physical Review Letters. Their paper is also posted at http://arxiv.org/abs/gr-qc/0702133.
Black holes represent the strongest gravitational fields in nature. These strong fields of gravity hold the black holes intact as they draw near and ultimately collapse upon each other. The collision creates waves of gravitational radiation that ripple outward through the galaxy at the speed of light, just slightly less than 300,000 kilometers per second, and kick the black holes out.
Campanelli's team carried out new computer simulations that follow the merger of two spinning black holes. The black holes merge while spinning at the same speed but in different directions. Based on the simulations, the team of scientists-which includes Carlos Lousto, Yosef Zlochower and David Merritt--determined that supermassive black holes could be ejected from a galaxy at the speed of 4,000 kilometers per second. In contrast, non-spinning black holes can only be kicked from galaxies with speeds of about 200 kilometers per second.
"The magnitude of the kick comes from the spin orientation of the black holes," says Campanelli, director of the new Center for Computational Relativity and Gravitation in RIT's School of Mathematical Sciences. "This was shocking to the astrophysical community. People knew that the black-hole spins would affect kicks, but not to this extent."
A black hole ejected from a galaxy at 4,000 kilometers per second moves only at a fraction of the speed of light. At that rate, the speed significantly exceeds the galaxy escape velocity, which is how fast the black hole has to be kicked to completely leave the galaxy-or 1,000 to 2,000 kilometers per second for big galaxies.
Campanelli's group was also the first to study simulated mergers of black holes that were spinning in random directions. Their findings published in Astrophysical Journal Letters in December 2006 showed that the spin axis and tilt of the spin determined the biggest kicks.
The team observed changes in the gravitational field when spinning black holes collided. Their results depart from most previous studies, which focus on idealized black holes-non-spinning or symmetrical in size. Campanelli's findings showed spinning black holes wobbling like a top and confirmed the spin-flip phenomenon that occurs when the remaining black hole in a merger changes its orientation.
Campanelli and her team also verified the occurrence of recoil or "kick" that forms the basis of their current findings.
"Predicting kick helped us understand if black holes can get ejected from a large galaxy," Campanelli says.
"A kicked black hole will carry with it any gas that is tightly enough bound to it before the merger," says Merritt, a professor of physics at RIT. "The black hole could continue to shine until it had swallowed this gas."
According to Merritt, small galaxies probably also lack black holes because the low escape velocities do not contain them.
Even though a black hole is only about one-tenth of one percent of the size of a galaxy, its sudden expulsion will shift matter in the galaxy.
"It does change central properties of a galaxy in ways people are beginning to think about," Merritt says. "The center of the galaxy expands. Gravity from the black hole is not there, so stars move farther from the center, 'puffing up'."
Alessia Gualandris, a post-doctoral fellow in RIT's Center for Computational Relativity and Gravitation, is currently looking at what happens when black holes are removed from a galaxy.
Most likely, an ejected black hole will eventually return to its position at the center of a galaxy, although that would take a long time, Merritt says.
Rochester Institute of Technology
Black holes represent the strongest gravitational fields in nature. These strong fields of gravity hold the black holes intact as they draw near and ultimately collapse upon each other. The collision creates waves of gravitational radiation that ripple outward through the galaxy at the speed of light, just slightly less than 300,000 kilometers per second, and kick the black holes out.
Campanelli's team carried out new computer simulations that follow the merger of two spinning black holes. The black holes merge while spinning at the same speed but in different directions. Based on the simulations, the team of scientists-which includes Carlos Lousto, Yosef Zlochower and David Merritt--determined that supermassive black holes could be ejected from a galaxy at the speed of 4,000 kilometers per second. In contrast, non-spinning black holes can only be kicked from galaxies with speeds of about 200 kilometers per second.
"The magnitude of the kick comes from the spin orientation of the black holes," says Campanelli, director of the new Center for Computational Relativity and Gravitation in RIT's School of Mathematical Sciences. "This was shocking to the astrophysical community. People knew that the black-hole spins would affect kicks, but not to this extent."
A black hole ejected from a galaxy at 4,000 kilometers per second moves only at a fraction of the speed of light. At that rate, the speed significantly exceeds the galaxy escape velocity, which is how fast the black hole has to be kicked to completely leave the galaxy-or 1,000 to 2,000 kilometers per second for big galaxies.
Campanelli's group was also the first to study simulated mergers of black holes that were spinning in random directions. Their findings published in Astrophysical Journal Letters in December 2006 showed that the spin axis and tilt of the spin determined the biggest kicks.
The team observed changes in the gravitational field when spinning black holes collided. Their results depart from most previous studies, which focus on idealized black holes-non-spinning or symmetrical in size. Campanelli's findings showed spinning black holes wobbling like a top and confirmed the spin-flip phenomenon that occurs when the remaining black hole in a merger changes its orientation.
Campanelli and her team also verified the occurrence of recoil or "kick" that forms the basis of their current findings.
"Predicting kick helped us understand if black holes can get ejected from a large galaxy," Campanelli says.
"A kicked black hole will carry with it any gas that is tightly enough bound to it before the merger," says Merritt, a professor of physics at RIT. "The black hole could continue to shine until it had swallowed this gas."
According to Merritt, small galaxies probably also lack black holes because the low escape velocities do not contain them.
Even though a black hole is only about one-tenth of one percent of the size of a galaxy, its sudden expulsion will shift matter in the galaxy.
"It does change central properties of a galaxy in ways people are beginning to think about," Merritt says. "The center of the galaxy expands. Gravity from the black hole is not there, so stars move farther from the center, 'puffing up'."
Alessia Gualandris, a post-doctoral fellow in RIT's Center for Computational Relativity and Gravitation, is currently looking at what happens when black holes are removed from a galaxy.
Most likely, an ejected black hole will eventually return to its position at the center of a galaxy, although that would take a long time, Merritt says.
Rochester Institute of Technology
Black Holes Current Events and Black Holes News RSSNew study confirms exotic electric properties of graphene
First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: a remarkably flat molecule made of carbon atoms arranged in hexagonal rings much like molecular chicken wire.
Swift XMM-Newton Satellites Tune Into a Middleweight Black Hole
While astronomers have studied lightweight and heavyweight black holes for decades, the evidence for black holes with intermediate masses has been much harder to come by.
NASA's Fermi Telescope Detects Gamma-Ray From
Nearby galaxies undergoing a furious pace of star formation also emit lots of gamma rays, say astronomers using NASA's Fermi Gamma-ray Space Telescope.
New Celestial Map Gives Directions for GPS
Many of us have been rescued from unfamiliar territory by directions from a Global Positioning System (GPS) navigator. GPS satellites send signals to a receiver in your GPS navigator, which calculates your position based on the location of the satellites and your distance from them.
Fermi telescope caps its first year with a glimpse of space-time
During its first year of operations, NASA's Fermi Gamma Ray Space Telescope mapped the extreme sky with unprecedented resolution and sensitivity.
New vista of Milky Way center unveiled
A dramatic new vista of the center of the Milky Way galaxy from NASA's Chandra X-ray Observatory exposes new levels of the complexity and intrigue in the Galactic center.
Invading black holes explain cosmic flashes
Black holes are invading stars, providing a radical explanation to bright flashes in the universe that are one of the biggest mysteries in astronomy today.
Swift Makes Best-ever Ultraviolet Portrait of Andromeda Galaxy
In a break from its usual task of searching for distant cosmic explosions, NASA's Swift satellite has acquired the highest-resolution view of a neighboring spiral galaxy ever attained in the ultraviolet.
Sophisticated telescope camera debuts with peek at nest of black holes
Less than two months after they inaugurated the world's largest telescope, University of Florida astronomers have used one of the world's most advanced telescopic instruments to gather images of the heavens.
COES professor's 'metamaterials' research lands cover of international journal
Dr. Dentcho Genov, an assistant professor of physics and electrical engineering at Louisiana Tech University and a Louisiana Optical Network Initiative (LONI) Institute fellow, is featured on the cover of the most recent issue of Nature Physics, one of the most respected and prestigious physics journals in the world.
More Black Holes Current Events and Black Holes News Articles
 |
Black Holes and Time Warps: Einstein's Outrageous Legacy (Commonwealth Fund Book Program) by Kip S. Thorne (Author), Stephen Hawking (Foreword) In this masterfully written and brilliantly informed work, Dr. Thorne, the Feynman Professor of Theoretical Physics at Caltech, leads readers through an elegant, always human, tapestry of interlocking themes, answering the great question: what principles control our universe and why do physicists think they know what they know? Features an introduction by Stephen Hawking. |
 |
National Geographic: Monster Black Holes Starring: Michael Carroll Travel to the edge of space and beyond to discover natures ultimate abyss black holes. Explore where they are found, how they begin, and how it may be possible to harness and use the power they produce. In Monster Black Holes, scientists steadily piece together the complex dynamics of a black holes birth and are also examine the growth of a select few black holes to super massive proportions that dominate the centers of galaxies. As a monster black hole swallows everything in its path, it generates energy that shapes the universe around it in powerful ways. Journey into the heart of a black hole and explore what happens to matter when it falls into a black hole, and whether the Milky Way galaxy will one day come to an end when the black hole at the galaxys center explodes. |
 |
Death by Black Hole: And Other Cosmic Quandaries by Neil deGrasse Tyson (Author) “One of today’s best popularizers of science.”—Kirkus Reviews Loyal readers of the monthly “Universe” essays in Natural History magazine have long recognized Neil deGrasse Tyson’s talent for guiding them through the mysteries of the cosmos with stunning clarity and childlike enthusiasm. Here Tyson compiles his favorite essays across a myriad of cosmic topics. The title essay introduces readers to the physics of black holes by explaining just what would happen to your body if you fell into one, while “Hollywood Nights” assails Hollywood’s feeble efforts to get its night skies right. Tyson is the world’s ... |
 |
Black Holes: And Other Bizarre Space Objects (Science Frontiers) by David Jefferis (Author) |
 |
The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics by Leonard Susskind (Author) At the beginning of the 21st century, physics is being driven to very unfamiliar territory--the domain of the incredibly small and the incredibly heavy. The new world is a world in which both quantum mechanics and gravity are equally important. But mysteries remain. One of the biggest involved black holes. Famed physicist Stephen Hawking claimed that anything sucked in a black hole was lost forever. For three decades, Leonard Susskind and Hawking clashed over the answer to this problem. Finally, in 2004, Hawking conceded. THE BLACK HOLE WAR will explain the mind-blowing science that finally won out, and the emergence of a new paradigm that argues the world--this catalog, your home, your breakfast, you--is actually a hologram projected from the edges of... |
 |
The Black Hole Starring: Ernest Borgnine, Joseph Bottoms, Robert Forster, Roddy McDowall, Tommy McLoughlin Also With: Anthony Perkins (Primary Contributor), Maximilian Schell (Primary Contributor) THE CREW OF THE SPACESHIP PALAMINO STUMBLES ACROSS THE LOST SHIP USS CYGNUS HOVERING ON THE EDGE OF AN IMMENSE BLACK HOLE. ONCE ABOARD THEY FIND THE SHIP IS MANNED BY ROBOTS ITS ONLY HUMAN INHABITANT ONE DR HANS REINHARDT AN EMINENT SCIENTIST MISSING FOR THE PAST TWENTY YEARS. |
 |
Exploring Black Holes: Introduction to General Relativity by Edwin F. Taylor (Author), John Archibald Wheeler (Author) Makes a quick, directed thrust through general relativity and black holes. Brings preliminary insights concerning the history and structure of the Cosmos. DLC: General relativity (Physics) |
 |
Mysterious Universe: Supernovae, Dark Energy, and Black Holes (Scientists in the Field Series) by Ellen Jackson (Author), Nic Bishop (Photographer) |
 |
Black Holes and Revelations by Muse In 2004, U.K. favorite Muse broke through in the U.S. with Absolution and major performances across America that won legions of new fans. In 2006, Muse takes a bold new step with Black Holes And Revelations, a powerful, upbeat epic album that takes the band’s music to a whole dimension. Once again co-produced by Rich Costey (Rage Against The Machine, Audioslave), Muse incorporates influences from electronica and Prince to pure pop. The album is sure to be a revelation to those still unfamiliar with the 2005 Brit award winner for Best Live Act who headlines this summer’s Reading and Leeds festivals. |
 |
Black Holes Directed By: Gregory Zorzos Also With: Gregory Zorzos (Producer), Gregory Zorzos (Writer) In general relativity, a black hole is a region of space in which the gravitational field is so powerful that nothing, not even light, can escape. In this movie you can see this phenomenon form many sources. This product is manufactured on demand using DVD-R recordable media. Amazon.com's standard return policy will apply. |
| © 2009 BrightSurf.com |