Re: Why is the crab nebula still such a potent synchrotron source?

Thank you for your question Royce. The Crab Nebula is actually the debris 
and stellar corpse of one of the great wonders of nature - a supernova. 
This supernova was witnessed here on earth - by the Chinese in the year 
1054 AD.

Supernovae occur when very massive stars exhaust their nuclear fuel. 
Massive stars, stars many times the mass of our sun, live short, violent 
lives. The intense gravity allows thermonuclear fusion to occur creating 
a variety of new elements - Carbon, Oxygen,... but when it reaches Iron, 
one can no longer use fusion to release energy. Without the fusion 
reaction to balance gravity, the star rapidly and catastrophically 
collapses. For stars about 4 to 8 times as massive as our sun, the 
stellar collapse is stopped by superdense material. The core reaches the 
density of an atomic nucleus, but with a diameter of a city. A "neutron 
star" is born - superhot, compressed matter containing about 1.4 times 
the mass of our sun, but in an approximate 20 km diameter.

Gravity forces protons and electrons together, creating the neutron star. 
But incredible density and surface gravity are not its only attributes. 
Neutron stars also possess some of the highest magnetic fields in the 
universe. And many of these neutron stars spin, creating "pulsars". 
Particles like electrons and protons in the debris cloud, become trapped 
along magnetic field lines and spiral inward toward the neutron star. 
This is similar to the way particles follow earth's magnetic field lines 
to create the auroras. But a neutron star has much higher gravitational 
field and those particles can be accelerated to much higher energies. 
This is the source of the synchrotron radiation. Particles interacting 
with a spinning, massive supercompact star with magnetic fields around a 
million x million guass provides the powerhouse for a broad spectrum of 
radiation.

Some general links for reference:
 http://www.astro.umd.edu/~miller/nstar.html
 http://csep10.phys.utk.edu/astr162/lect/pulsars/pulsars.html