Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Firehose-like jet discovered in action

01.07.2003


Photo: Chandra image of the Vela pulsar (NASA/CXC/Penn State/G. Pavlov et al.)


An X-ray movie of the Vela pulsar, made from a series of observations by NASA’s Chandra X-ray Observatory, reveals a spectacularly erratic jet that varies in a way never seen before. The jet of high-energy particles whips about like an untended firehose at about half the speed of light. This behavior gives scientists new insight into the nature of jets from pulsars and black holes.

Chandra observed the Vela pulsar, a rotating neutron star, 13 times between January 2000 and August 2002. These observations, which were designed to study the nature of the outflow of matter and antimatter from the pulsar led to the discovery that an outer jet of particles was bending and moving sideways at phenomenal speeds.

"This jet is half a light year in length, and is shooting out ahead of the moving pulsar," said George Pavlov of Pennsylvania State University in University Park, lead author of a paper in the July 10th issue of The Astrophysical Journal. "The most striking thing about this jet is how rapidly it changes both its shape and brightness. Such strong, fast variability has never been observed in astrophysical jets."



The time-lapse movie shows that in a matter of weeks the jet changes from being straight to hook-shaped, while bright blobs move along the jet at about half the speed of light. The jet is composed of extremely high-energy electrons or positrons (an antimatter form of electrons) that are spiraling around a magnetic field. The particles in the jet are created and accelerated by voltages 100 million times that of a lightning bolt. These voltages produced by the combined action of the fast rotation of the neutron star and its intense magnetic field.

Over its entire length, the width of the jet remains approximately constant. This suggests that the jet is confined by magnetic fields generated by electrons flowing along the axis of the jet. Laboratory studies of jets or beams have shown that they can change rapidly due to an effect called the "firehose instability."

"Imagine a firehose lying on the ground," said Marcus Teter, also of Penn State and co-author on the paper. "After you turn on the water, you will see different parts of the hose kinking up, and moving rapidly in different directions, pushed by the increased pressure at the bends in the hose. The Vela jet resembles a hose made of magnetic fields, which confines the electrically charged particles."

The instability could be triggered by the strong head-wind created as the pulsar moves through the surrounding gas at a speed of 300,000 kilometer per hour (about 200,000 miles per hour). The bright blobs in the jet are thought to be a manifestation of the increased magnetic field and particle pressure at the kinks in the jet.

The observed brightness of the outer jet and the rapid motions of the jet and blobs in it indicate that the bright arcs around the pulsar may not be rings circling its equator, as previously thought. Instead, they may represent shock waves caused by the motion of the inner jet through the cloud of particles around the pulsar.

"The study of pulsar jets is important not only in itself," said Oleg Kargaltsev, a Penn State graduate student and co-investigator, "but it could also help to understand the nature of the enormous jets coming from supermassive black holes. Those jets may also vary, but on time scales of millions of years, instead of weeks as in the Vela pulsar jet."

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Steve Roy | EurekAlert!
Further information:
http://chandra.nasa.gov
http://www1.msfc.nasa.gov/NEWSROOM/news/releases/2003/03-103.html

More articles from Physics and Astronomy:

nachricht Discovery of an Extragalactic Hot Molecular Core
29.09.2016 | National Astronomical Observatory of Japan

nachricht Swiss space research reaches for the sky
29.09.2016 | Schweizerischer Nationalfonds SNF

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: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

Laser use for neurosurgery and biofabrication - LaserForum 2016 focuses on medical technology

27.09.2016 | Event News

 
Latest News

New Multiferroic Materials from Building Blocks

29.09.2016 | Materials Sciences

Silicon Fluorescent Material Developed Enabling Observations under a Bright “Biological Optical Window”

29.09.2016 | Materials Sciences

X-shape Bio-inspired Structures

29.09.2016 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>