Anomalous X-Ray Pulsar

An extremely rare type of the more common X-Ray Pulsar, only a handful are known to exist in the entire Galaxy. AXP's are the spinning cores of dead stars, known as neutron stars, sweeping beams of energy through space like a cosmic lighthouse.

AXP's are magnetars, neutron stars with enormously strong magnetic fields. Created from the core of a gigantic star that has exploded at the end of its life, each magnetar is only around 15 kilometers in diameter yet contains the mass of a standard main sequence dwarf star.

Magnetars are also responsible for the soft gamma-ray repeaters (SGRs) which explosively release massive quantities of energy when catastrophic reorganisations of their magnetic fields spontaneously take place. The big difference between an SGR and an AXP is that the process is continuous rather than explosive in an AXP and less energetic. Somehow these objects are tapping the enormous magnetic energy contained beneath their surfaces and funneling it into space.

It is possible that SGRs turn into AXPs once they have exploded enough of their energy into space.

Most known AXPs are clustered towards the plane of our galaxy, the Milky Way, indicating that they are the result of recent stellar explosions; some are even wreathed in the exploded gaseous remnants of their former stars.