Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New study shows how black holes get their ’kicks’

04.02.2004


RIT professor researches black-hole mergers



When black holes collide, look out! An enormous burst of gravitational radiation results as they violently merge into one massive black hole. The "kick" that occurs during the collision could knock the black hole clear out of its galaxy.

A new study describes the consequences of such an intergalactic collision.


Astrophysicist David Merritt, professor at Rochester Institute of Technology, and co-authors Milos Milosavljevic (Caltech), Marc Favata (Cornell University), Scott Hughes (Massachusetts Institute of Technology) and Daniel Holz (University of Chicago) explore the consequences of kicks induced by gravitational waves in their article, "Consequences of Gravitational Radiation Recoil," recently submitted to The Astrophysical Journal and posted online at http://arXiv.org/abs/astro-ph/0402057 after 8 p.m. on February 3, EST.

Virtually all galaxies are believed to contain supermassive black holes at their centers. According to current theory, galaxies grow through mergers with other galaxies. When two galaxies merge, their central black holes form a binary system and revolve around each other, eventually coalescing into a single black hole. The coalescence is driven by the emission of gravitational radiation, as predicted by Einstein’s theory of relativity.

Merritt and his colleagues determined how fast a black hole has to move to completely escape a galaxy’s gravitational field. They found that larger and brighter galaxies have stronger gravitational fields and would require a bigger kick to eject a black hole than the smaller systems. Likewise, less forceful impacts could jar the black hole out of its home at the center of a galaxy, only to later rebound back into position.

The kicks also call into question theories that would grow supermassive black holes from hierarchical mergers of smaller black holes, starting in the early universe. "The reason is that galaxies were smaller long ago, and the kicks would easily have removed the black holes from them," Merritt says.

According to Merritt and his co-authors, it’s more likely that supermassive black holes attained most of their mass through the accretion of gas and that mergers with other black holes only took place after the galaxies had reached roughly their current sizes.

"We know that supermassive black holes exist at the centers of giant galaxies like our own Milky Way," says Merritt. "But as far as we know, the smaller stellar systems do not have any black holes. Perhaps they used to, but they were kicked out."

The kick--a consequence of Einstein’s relativity equations--occurs because gravitational waves emitted during the final plunge are anisotropic, producing recoil. The effect is maximized when one black hole is appreciably larger than the other one. While astrophysicists have been aware of this phenomenon since the 1960s, until now no one has had the analytical tools necessary to accurately calculate the size of the effect. The first accurate calculation of the size of the kicks was reported in a companion paper by Favata, Hughes and Holz, which also appears online at http://arXiv.org.

Merritt notes that there is no clear observational evidence that the kicks have taken place. He contends that the best chance of finding direct evidence would be locating a black hole shortly after the kick occurs, perhaps in a galaxy that has recently undergone a merger with another galaxy.

"You would see an off-center black hole that hasn’t quite made its way back to the center yet," he says. "Even though the probability of observing this is low, now that astronomers know what to look for, I wouldn’t be surprised if someone finds one eventually."


###
NOTE: To talk to David Merritt, call 908-420-7942, or contact Susan Gawlowicz at 585-475-5061 or smguns@rit.edu.

Susan Gawlowicz | EurekAlert!
Further information:
http://www.rit.edu/
http://arXiv.org/abs/astro-ph/0402057

More articles from Physics and Astronomy:

nachricht When fluid flows almost as fast as light -- with quantum rotation
22.06.2018 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

nachricht Thermal Radiation from Tiny Particles
22.06.2018 | Universität Greifswald

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>