This image from NASA's Chandra X-ray Observatory and ground-based optical telescopes shows an extremely long beam, or filament, of matter and antimatter extending from a relatively tiny pulsar, as reported in our latest press release. With its tremendous scale, this beam may help explain the surprisingly large numbers of positrons, the antimatter counterparts to electrons, scientists have detected throughout the Milky Way galaxy.
The panel on the left displays about one third the
length of the beam from the pulsar known as PSR J2030+4415 (J2030 for short),
which is located about 1,600 light years from Earth. J2030 is a dense, city-sized object that formed from
the collapse of a massive star and currently spins about three times per
second. X-rays from Chandra
(blue) show where particles flowing from the pulsar along magnetic field lines
are moving at about a third the speed of
light. A close-up view of the pulsar in the
right panel shows the X-rays created by particles flying around the pulsar
itself. As the pulsar moves through space at about a million miles an hour,
some of these particles escape and create the long filament. In both panels, optical light data
from the Gemini telescope on Mauna Kea in Hawaii have been used and appear red,
brown, and black. The full length of the filament is shown in a separate image.
The vast majority of the Universe consists of ordinary
matter rather than antimatter. Scientists, however, continue to find evidence for relatively large
numbers of positrons in detectors on Earth, which leads to the question: what
are possible sources of this antimatter? The researchers in the new Chandra
study of J2030 think that pulsars like it may be one answer. The combination of
two extremes — fast rotation and high magnetic fields of pulsars — lead to
particle acceleration and high energy radiation that creates electron and
positron pairs. (The usual process of converting mass into energy famously
determined by Einstein's E = mc2 equation
is reversed, and energy is converted into mass.)
Pulsars generate winds of charged particles that are
usually confined within their powerful magnetic fields.
The pulsar is traveling through interstellar space at about half a million
miles per hour, with the wind trailing behind it. A bow shock of gas moves
along in front of the pulsar, similar to the pile-up of water in front of a
moving boat. However, about 20 to 30 years ago the bow shock's motion appears
to have stalled and the pulsar caught up to it.
The ensuing collision likely triggered a particle
leak, where the pulsar wind's magnetic field linked up with the interstellar
magnetic field. As a result, the high-energy electrons and positrons could have
squirted out through a "nozzle" formed by connection into the Galaxy.
Previously, astronomers have observed large halos
around nearby pulsars in gamma-ray light that imply energetic positrons generally
have difficulty leaking out into the Galaxy. This undercut the idea that
pulsars explain the positron excess that scientists detect. However, pulsar
filaments that have recently been discovered, like J2030, show that particles
actually can escape into interstellar space, and eventually could reach Earth.
A paper describing these results, authored by Martjin
de Vries and Roger Romani of Stanford University, will appear in The
Astrophysical Journal and is available online.
NASA's Marshall Space Flight Center manages the Chandra program. The
Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science
operations from Cambridge, Massachusetts, and flight operations from
Burlington, Massachusetts.
Image credit: X-ray: NASA/CXC/Stanford Univ./M. de
Vries; Optical: NSF/AURA/Gemini Consortium
Read more from NASA's Chandra X-ray Observatory.
For more Chandra images, multimedia and related
materials, visit: http://www.nasa.gov/chandra
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