What exactly are Magnetars? I've heard the term used before, and all I

[fillipeano]

What exactly are Magnetars? I've heard the term used before, and all I remember about them are that they have very powerful magnetic fields.
What are they? How do they form and how do we detect them?

 

[nicksauce]

They arehttp://en.wikipedia.org/wiki/Neutron_star" with extraordinarily large magnetic fields.

 

[fillipeano]

How do they get such a large magnetic field? I'm really intrigued by strange objects :)

 

[Orion1]

What exactly are Magnetars?

A magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious amounts of high-energy electromagnetic radiation, particularly X-rays and gamma rays.

How do they get such a large magnetic field?

Magnetars are primarily characterized by their extremely powerful magnetic field, which can often reach the order of ten gigateslas.

A 10 gigatesla field, by contrast, has an energy density of $$4.0 \times 10^{25} \; \frac{\text{J}}{\text{m}^3}$$.

Although most common magnetic phenomena are electromagnetic, a second source of magnetism occurs due to the spin magnetic moment of sub-atomic particles. Spin magnetic moment is responsible for the magnetic field of magnetars.

Reference:
http://en.wikipedia.org/wiki/Neutron_star"
http://en.wikipedia.org/wiki/Magnetar"
http://en.wikipedia.org/wiki/Spin_magnetic_moment"

 

[SpiffyKavu]

... How do they form and how do we detect them?

Magnetars are a special type of neutron stars, which are a result of the evolution of a massive star. The star undergoes a supernova explosion, and a neutron star is left from the core of the star.

Magnetars have specific timing properties like radio pulsars. Unlike pulsars, however, magnetars have long spin periods (2-8 seconds or so) and are not very bright in radio emission. The magnetic field is so strong that it will deform the crust of the neutron star periodically. This results in the emission of high energy x-rays (hard x-rays) or lower energy gamma rays (soft gamma rays). These objects are respectively called anomalous X-ray pulsars (AXP) and soft gamma repeaters (SGR)