MAGNETARS

Magnetars are neutron stars with the strongest magnetic fields in the Universe. They probe extreme physical conditions, such as strong field gravity, huge (nuclear) densities and extreme energy densities. The evolution and decay of their ultra-strong magnetic field powers a variety of X-ray bursting activity, ranging from relatively frequent short bursts to very rare and much more energetic giant flares. This makes magnetars relatively short lived objects, and is the reason why only a few dozen are known to exist in the Galaxy, despite the fact that a large fraction of neutron stars are thought to begin their lives in this state (1).

While typical Galactic magnetars spin around their axis once every several seconds, they might be born spinning as fast as a thousand times a second. Such newly born magnetars have been suggested as the fire-houses powering various astrophysical transients, and their are ongoing inquiries regarding the validity of these associations (2,3,4,5). 

At the other extreme, recent discoveries of extremely long period Galactic objects (6,7,8), hint at the existence of a large, and previously unknown population of ultra-long period magnetars whose periods could be hours long or more (9). This corroborates earlier suggestions based on FRB periodicities (10).