Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Reveals a Remarkable Symmetry in Black Hole Jets

14.12.2012
Black holes range from modest objects formed when individual stars end their lives to behemoths billions of times more massive that rule the centers of galaxies.

A new study using data from NASA's Swift satellite and Fermi Gamma-ray Space Telescope shows that high-speed jets launched from active black holes possess fundamental similarities regardless of mass, age or environment. The result provides a tantalizing hint that common physical processes are at work.


Astronomers examining the properties of black hole jets compared 54 gamma-ray bursts with 234 active galaxies classified as blazars and quasars. Surprisingly, the power and brightness of the jets share striking similarities despite a wide range of black hole mass, age and environment. Regardless of these differences, the jets produce light by tapping into similar percentages of the kinetic energy of particles moving along the jet, suggesting a common underlying physical cause.
Credit: NASA's Goddard Space Flight Center

"What we're seeing is that once any black hole produces a jet, the same fixed fraction of energy generates the gamma-ray light we observe with Fermi and Swift," said lead researcher Rodrigo Nemmen, a NASA Postdoctoral Program (NPP) fellow at NASA's Goddard Space Flight Center in Greenbelt, Md.

Gas falling toward a black hole spirals inward and piles up into an accretion disk, where it becomes compressed and heated. Near the inner edge of the disk, on the threshold of the black hole's event horizon -- the point of no return -- some of the material becomes accelerated and races outward as a pair of jets flowing in opposite directions along the black hole's spin axis. These jets contain particles moving at nearly the speed of light, which produce gamma rays -- the most extreme form of light -- when they interact.

"We don't fully understand how this acceleration process occurs, but in active galaxies we see jets that have operated so long that they've produced trails of gas extending millions of light-years," said Sylvain Guiriec, an NPP fellow at Goddard and a co-author on the study, which was published in the Dec. 14 issue of Science.

At the other end of the scale are gamma-ray bursts (GRBs), the most powerful explosions in the universe. Astronomers believe that the most common type of GRB heralds the death of a massive star and the birth of a stellar-mass black hole. When the star's energy-producing core runs through its store of fuel, it collapses and forms a black hole. As the star's overlying layers cascade inward, an accretion disk forms and the black hole launches a jet.

The particles in some GRB jets have been clocked at speeds exceeding 99.9 percent the speed of light. When the jet breaches the star's surface, it produces a pulse of gamma rays typically lasting a few seconds. Satellites like Swift and Fermi can detect this emission if the jet is approximately directed toward us.

To search for a trend across a wide range of masses, the scientists looked at the galactic-scale equivalent of GRB jets. These come from the brightest classes of active galaxies, blazars and quasars, which sport jets that likewise happen to point our way.

To match the amount of energy given off by a typical blazar in one second, the sun must shine for 317,000 years. To equal the energy a run-of-the-mill GRB puts out in one second, the sun would need to shine for another 3 billion years.

Ultimately, the team examined 54 GRBs and 234 blazars and quasars. The gamma-ray brightness obtained with Fermi, Swift and other observatories told the scientists how much light the jets radiate. Radio and X-ray observations allowed them to determine the power of the particle acceleration in each jet. By analyzing how these two properties related to each other, the researchers discovered that the GRB and blazar samples both exhibited the same relationship.

"Here we have a situation where the mechanism that launches material from a black hole either has to be very similar on both ends of the mass scale -- from a few to a billion solar masses -- or we need different mechanisms that manage to produce very similar efficiencies," explained co-author Eileen Meyer, a post-doctoral researcher at the Space Telescope Science Institute in Baltimore.

The finding simplifies astronomers' understanding of black holes by showing that their activity is governed by the same set of rules -- whatever they happen to be -- independent of mass, age, or the jet's brightness and power. The jets tap into similar fractions -- between 3 and 15 percent -- of the energy wrapped up in the motion of their accelerated particles to power the emission of gamma rays and other forms of light.

"It's a bit like a poor man and a billionaire spending the same percentage of their incomes on their heating bills," said team member Markos Georganopoulos, an associate professor of physics at the University of Maryland, Baltimore County.

The authors hope to extend the research to other black-hole-powered events that launch jets, such as the tidal disruption of stars by supermassive black holes.

"One especially useful outcome of this research will be to foster greater communication between astronomers studying GRBs and those working on active galaxies, which in the past we've tended to regard as separate areas of study," said co-author Neil Gehrels, the principal investigator on NASA's Swift.

Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Md.

Francis Reddy | EurekAlert!
Further information:
http://www.nasa.gov/topics/universe/features/black-hole-symmetry.html

More articles from Physics and Astronomy:

nachricht Telescopes team up to find distant Uranus-sized planet through microlensing
31.07.2015 | NASA/Goddard Space Flight Center

nachricht California 'rain debt' equal to average full year of precipitation
31.07.2015 | NASA/Goddard Space Flight Center

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: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Tool making and additive technology exhibition: Fraunhofer IPT at Formnext

31.07.2015 | Trade Fair News

First Siemens-built Thameslink train arrives in London

31.07.2015 | Transportation and Logistics

California 'rain debt' equal to average full year of precipitation

31.07.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>