Featured Research

from universities, journals, and other organizations

Secrets Of Massive Black Hole Unveiled: Workings Of Giant Galactic Particle Accelerators Discovered

Date:
April 24, 2008
Source:
National Radio Astronomy Observatory
Summary:
At the cores of many galaxies, supermassive black holes expel powerful jets of particles at nearly the speed of light. Just how they perform this feat has long been one of the mysteries of astrophysics. Now, astronomers have watched material winding a corkscrew outward path and behaving exactly as predicted by a leading theory.

Artist's conception of region near supermassive black hole where twisted magnetic fields propel and shape jet of particles.
Credit: Marscher et al., Wolfgang Steffen, Cosmovision, NRAO/AUI/NSF

At the cores of many galaxies, supermassive black holes expel powerful jets of particles at nearly the speed of light. Just how they perform this feat has long been one of the mysteries of astrophysics. The leading theory says the particles are accelerated by tightly-twisted magnetic fields close to the black hole, but confirming that idea required an elusive close-up view of the jet's inner throat. Now, using the unrivaled resolution of the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA), astronomers have watched material winding a corkscrew outward path and behaving exactly as predicted by the theory.

"We have gotten the clearest look yet at the innermost portion of the jet, where the particles actually are accelerated, and everything we see supports the idea that twisted, coiled magnetic fields are propelling the material outward," said Alan Marscher, of Boston University, leader of an international research team. "This is a major advance in our understanding of a remarkable process that occurs throughout the Universe," he added.

Marscher's team studied a galaxy called BL Lacertae (BL Lac), some 950 million light-years from Earth. BL Lac is a blazar, the most energetic type of black-hole-powered galactic core. A black hole is a concentration of mass so dense that not even light can escape its gravitational pull. Supermassive black holes in galaxies' cores power jets of particles and intense radiation in similar objects including quasars and Seyfert galaxies.

Material pulled inward toward the black hole forms a flattened, rotating disk, called an accretion disk. As the material moves from the outer edge of the disk inward, magnetic field lines perpendicular to the disk are twisted, forming a tightly-coiled bundle that, astronomers believe, propels and confines the ejected particles. Closer to the black hole, space itself, including the magnetic fields, is twisted by the strong gravitational pull and rotation of the black hole.

Theorists predicted that material moving outward in this close-in acceleration region would follow a corkscrew-shaped path inside the bundle of twisted magnetic fields. They also predicted that light and other radiation emitted by the moving material would brighten when its rotating path was aimed most directly toward Earth.

Marscher and his colleagues predicted there would also be a flare later when the material hits a stationary shock wave called the "core" some time after it has emerged from the acceleration region.

"That behavior is exactly what we saw," Marscher said, when his team followed an outburst from BL Lac. In late 2005 and early 2006, the astronomers watched BL Lac with an international collection of telescopes as a knot of material was ejected outward through the jet. As the material sped out from the neighborhood of the black hole, the VLBA could pinpoint its location, while other telescopes measured the properties of the radiation emitted from the knot.

Bright bursts of light, X-rays, and gamma rays came when the knot was precisely at locations where the theories said such bursts would be seen. In addition, the alignment of the radio and light waves -- a property called polarization -- rotated as the knot wound its corkscrew path inside the tight throat of twisted magnetic fields.

"We got an unprecedented view of the inner portion of one of these jets and gained information that's very important to understanding how these tremendous particle accelerators work," Marscher said.

In addition to the continent-wide VLBA, an array of 10 radio telescopes spread from Hawaii to the Virgin Islands, the team used telescopes at the Steward Observatory, the Crimean Astrophysical Observatory, Lowell Observatory, Perugia University Astronomical Observatory, Abastumani Astrophysical Observatory, NASA's Rossi X-Ray Timing Explorer, the University of Michigan Radio Astronomy Observatory, and the Metsahovi Radio Observatory. The astronomers reported their findings in the April 24 issue of the journal Nature.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


Story Source:

The above story is based on materials provided by National Radio Astronomy Observatory. Note: Materials may be edited for content and length.


Cite This Page:

National Radio Astronomy Observatory. "Secrets Of Massive Black Hole Unveiled: Workings Of Giant Galactic Particle Accelerators Discovered." ScienceDaily. ScienceDaily, 24 April 2008. <www.sciencedaily.com/releases/2008/04/080423131621.htm>.
National Radio Astronomy Observatory. (2008, April 24). Secrets Of Massive Black Hole Unveiled: Workings Of Giant Galactic Particle Accelerators Discovered. ScienceDaily. Retrieved September 24, 2014 from www.sciencedaily.com/releases/2008/04/080423131621.htm
National Radio Astronomy Observatory. "Secrets Of Massive Black Hole Unveiled: Workings Of Giant Galactic Particle Accelerators Discovered." ScienceDaily. www.sciencedaily.com/releases/2008/04/080423131621.htm (accessed September 24, 2014).

Share This



More Space & Time News

Wednesday, September 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Hyped-Up Big Bang Discovery Has A Dust Problem

The Hyped-Up Big Bang Discovery Has A Dust Problem

Newsy (Sep. 22, 2014) — An analysis of new satellite data casts serious doubt on a previous study about the Big Bang that was once hailed as revolutionary. Video provided by Newsy
Powered by NewsLook.com
NASA's MAVEN Spacecraft Has Finally Reached Mars

NASA's MAVEN Spacecraft Has Finally Reached Mars

Newsy (Sep. 22, 2014) — After a 10-month voyage through space, NASA's MAVEN spacecraft is now orbiting the Red Planet. Video provided by Newsy
Powered by NewsLook.com
Raw: SpaceX Rocket Carries 3-D Printer to Space

Raw: SpaceX Rocket Carries 3-D Printer to Space

AP (Sep. 22, 2014) — A SpaceX Rocket launched from Cape Canaveral, carrying a custom-built 3-D printer into space. NASA envisions astronauts one day using the printer to make their own spare parts. (Sept. 22) Video provided by AP
Powered by NewsLook.com
SpaceX Cargo Ship Blasts Off Toward Space Station

SpaceX Cargo Ship Blasts Off Toward Space Station

AFP (Sep. 21, 2014) — SpaceX's unmanned Dragon cargo ship blasts off toward the International Space Station, carrying a load of supplies and science experiments for the astronauts living there. Duration: 00:35 Video provided by AFP
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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