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.
"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.
NASA's Goddard Space Flight Center, Greenbelt, Md.
Francis Reddy | Source: EurekAlert!
Further information: www.nasa.gov/topics/universe/features/black-hole-symmetry.html
Further Reports about: active galaxies > black hole > black populations > Fermi > gamma rays > gamma-ray burst > Goddard Space Flight Center > Greenbelt > Jets > remarkable > Reveals > Science TV > Space > Space Telescope > speed of light > speed|scan atlineCT-System > Telescope
More articles from Physics and Astronomy:
Hubble Uncovers Evidence for Extrasolar Planet Under Construction
17.06.2013 | Space Telescope Science Institute (STScI)
New quantum dot technique combines best of optical and electron microscopy
13.06.2013 | National Institute of Standards and Technology (NIST)
... two engines aircraft project “Elektro E6”.
The countdown has been started for opening the gates again for the worldwide leading aviation and space event in Le Bourget, Paris from June 17th - 23rd, 2013.
EADCO & PC-Aero will present at the Paris Air Show in Hall H4 booth F-7 their new future aircraft and innovative project: ...
Siemens scientists have developed new kinds of ceramics in which they can embed transformers.
The new development allows power supply transformers to be reduced to one fifth of their current size so that the normally separate switched-mode power supply units of light-emitting diodes can be integrated into the module's heat sink.
The new technology was developed in cooperation with industrial and research partners who ...
Cheaper clean-energy technologies could be made possible thanks to a new discovery.
Led by Raymond Schaak, a professor of chemistry at Penn State University, research team members have found that an important chemical reaction that generates hydrogen from water is effectively triggered -- or catalyzed -- by a nanoparticle composed of nickel and phosphorus, two inexpensive elements that are abundant on Earth. ...
The Fraunhofer Institute for Laser Technology ILT generated a lot of interest at the LASER World of Photonics 2013 trade fair with its numerous industrial laser technology innovations.
Its highlights included beam sources and manufacturing processes for ultrashort laser pulses as well as ways to systematically optimize machining processes using computer simulations. There was even a specialist booth at the fair dedicated to the revolutionary technological potential of digital photonic production.
Now in its fortieth year, LASER World ...
It's not reruns of "The Jetsons", but researchers working at the National Institute of Standards and Technology (NIST) have developed a new microscopy technique that uses a process similar to how an old tube television produces a picture—cathodoluminescence—to image nanoscale features.
Combining the best features of optical and scanning electron microscopy, the fast, versatile, and high-resolution technique allows scientists to view surface and subsurface features potentially as small as 10 nanometers in size.
The new microscopy technique, described in the journal AIP Advances,* uses a beam of electrons to excite a specially ...
17.06.2013 | Studies and Analyses
17.06.2013 | Health and Medicine
17.06.2013 | Life Sciences
14.06.2013 | Event News
13.06.2013 | Event News
10.06.2013 | Event News