The Geminga pulsar, the neutron star nearest
to the Earth, was recently observed by the XMM-Newton satellite. Scientists
detected two very long, symmetrical tails, created by the bow shock of
the matter emitted from the pulsar, which moves at supersonic speed. These
findings were published in the September 5, 2003, issue of Science
and are featured on the journal's cover.
The Geminga pulsar has been observed with the
XMM-Newton telescope of the ESA by an international team(1) including
researchers from the "Centre détude spatiale des rayonnements"
(CESR - CNRS, Paul Sabatier University in Toulouse, Midi-Pyrénées
Observatory). The observation data reveal the presence of two elongated,
symmetrical tails of X-ray light stretching more than one-third of a light
year. These are high-energy electrons confined by the interstellar shock
magnetic field. These two visible tails are in fact the two edges of a
cone created by the supersonic motion of Geminga in the interstellar medium.
The Geminga pulsar is a rapidly spinning neutron star. Geminga was observed
for the first time 30 years ago by Giovanni Bignami, who gave the star
its name. Geminga is a play on words in Milanese dialect that means "does
not exist." It is one of the nearest pulsars, located at a distance
of 500 light years from Earth.
1 - This international team is
made up of P.A. Caraveo (CNRS-Italy), G.F. Bignami (CESR-CNRS), A. DeLuca
(CNR-Italy), S. Mereghetti (CNR-Italy), A. Pellizzoni (CNR-Italy), R.
Mignani (ESO), A. Tur (CESR-CNRS), W. Becker (MPE-Germany)
Giovanni Bignami, CESR
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