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Summary - (Apr 8, 2005) A vast looping
structure 20 light-years across has been discovered near the heart of the
Milky Way. The loop was found near a star forming region of our galaxy in
the X-ray spectrum using the European Space Agency's XMM-Newton space
telescope. Very high energy particles, usually only seen coming from pulsars
or supernovae remnants, are streaming out of the object, so it could be
working as a kind of natural particle accelerator.
Full Story -
 Astronomers have
found a vast loop-like structure, 20 light years across, adjacent to the
most massive star-forming region known in our galaxy. The loop, which was
observed in X-ray wavelengths, is 15 times the size of the Arches Cluster, a
star-forming region close to the centre of the Milky Way. This is the first
time that such a distinctive and huge loop structure has been observed. Dr
Masaaki Sakano, from the University of Leicester, will be presenting the
discovery at the RAS National Astronomy Meeting at the University of
Birmingham on Friday 8th April.
The team of astronomers, which includes scientists from the University of
Leicester, CEA Saclay and the Max Planke Institute for Extraterrestrial
Physics, observed the Arches Cluster repeatedly using the European X-ray
satellite, XMM-Newton, as a part of the XMM-Newton Galactic Centre Survey.
The galactic centre can only be observed at certain wavelengths, such as
X-rays, because large amounts of dust lie in our line of sight and this
blocks out optical light.
Dr Sakano says, "The X-ray spectrum of the loop is extraordinary. Most
diffuse X-ray sources in the Universe have a characteristic temperature
because they are the residual radiation from an event, such as a supernova
explosion. However in this case the loop is non-thermal and this means that
whatever the origin of the structure is, it is not stationary but rather the
result of some ongoing process."
The most straightforward interpretation of the observations is that powerful
particle-acceleration is occurring on-site, producing high energy particles
with an energy of up to a thousand trillion electron volts (a thousand times
more energetic than those produced in man-made particle accelerators). Such
particles have been detected previously in a few supernova remnants and many
pulsar nebulae, where a very powerful central source has created them.
However, evidence for high-energy particles has never been observed before
in star-forming regions of our galaxy.
At this stage it is not clear whether the loop structure is physically
related to the Arches Cluster or just happens to be in our line of sight.
However, if future observations show that the Arches Cluster is responsible
for the feature, this discovery suggests that star-forming activity plays an
important role in the energetic Universe.
Original Source:
RAS News Release
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