The high-voltage environment of one of the most energetic and strongly
magnetized pulsars known has been surveyed by NASA’s Chandra X-ray
Observatory. A team of astronomers found a powerful jet of high-energy
particles extending over a distance of 20 light years and bright arcs
believed to be due to particles of matter and anti-matter generated by the
pulsar.
The team of US, Canadian, and Japanese scientists pointed Chandra at the
rapidly spinning neutron star B1509-58, located 19,000 light years away in
the constellation of Circinus, for over five hours. These results were
announced at the “Two Years of Science with Chandra” symposium in Washington,
D.C.
“Jets and arcs on this vast scale have never been seen in any other pulsar,”
said Bryan Gaensler of the Smithsonian Astrophysical Observatory. “The
spectacular images we have obtained of this source are letting us test
theories as to how pulsars unleash so much energy.”
The features seen with Chandra give the scientists insight into the process
by which voltages of more than 7000 trillion volts are created around
rotating neutron stars (the dense remnants of supernova explosions) and
how these extreme voltages affect their environment. B1509-58 is of
particular interest because it has a much stronger magnetic field than the
Crab Nebula pulsar, which exhibits similar features on a much smaller scale.
The general picture emerging from these results is that high-energy particles
of matter and antimatter are streaming away from the neutron star along its
poles and near its equator. The particles leaving the poles produce the
jets; astronomers speculate that only one side of the jet is apparent in
B1509-58, indicating that this one side is beamed in our direction, while
the other is rushing away.
“Until this observation, no one knew for sure whether such tremendous
voltages and energy outputs were a trademark of all pulsars, or if the Crab
was an oddball,” said Vicky Kaspi of McGill University in Montreal. “Now
thanks to Chandra, it is becoming clear that pulsars are stupendous cosmic
power plants.”
The arcs are thought to be due to shock waves in matter flowing away from
the equator of the pulsar. By measuring the position and width of these
arcs, the team estimated the intensity of the magnetic field, and the rate
at which the pulsar is pumping high-energy particles into the space around
it.
“The X-ray images give us evidence that the pulsar not only accelerates
particles efficiently,” said Jonathan Arons of the University of California
at Berkeley, “but it gives them energy comparable to the highest energies
found in the cosmic rays which continuously bombard the Earth.”
In addition, the team determined that a bright cloud of X-ray emission about
25 light years from the pulsar is due to multi-million degree gas. This hot
cloud was probably produced as material ejected by the supernova collided
with cooler gas in interstellar space.
Other members of the B1509-58 research team included Michael Pivovaroff
(ThermaWave Inc), Nobuyuki Kawai (Tokyo Institute of Technology) and
Keisuke Tamura (Nagoya University).
Chandra observed B1509-58 with its Advanced CCD Imaging Spectrometer
(ACIS) instrument, which was developed for NASA by Pennsylvania State
University, University Park, and Massachusetts Institute of Technology,
Cambridge. NASA’s Marshall Space Flight Center in Huntsville, Ala, manages
the Chandra program, and TRW, Inc., Redondo Beach, Calif., is the prime
contractor for the spacecraft. The Smithsonian’s Chandra X-ray Center
controls science and flight operations from Cambridge, Mass.
Images associated with this release are available on the World Wide Web at:
AND
IMAGE CAPTION:
[http://www1.msfc.nasa.gov/NEWSROOM/news/photos/2001/photos01-299.htm]
This Chandra image gave astronomers their first view of the energetic and
complex nebula surrounding the young pulsar PSR B1509-58. The blue and
purple colors indicate X-rays emitted by high-energy particles of matter
and anti-matter which stream away from the pulsar. The pulsar itself is
the bright white source at the center of the nebula.
A thin jet, almost 20 light years in length, extends to the lower left, and
traces a beam of particles being shot out from the pulsar’s south pole at
more than 130 million miles per hour. Just above the pulsar can be seen a
small arc of X-ray emission, which marks a shock wave produced by particles
flowing away from the pulsar’s equator.
The green cloud near the top of the image is due to multimillion degree
Celsius gas. This gas, possibly a remnant of the supernova explosion
associated with the creation of the pulsar, may have been heated by
collisions with high-energy particles produced by the pulsar.
Credit: NASA/MIT/B. Gaensler et al.
