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 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 >>>