Known Magnetars
As of April 2011, twenty-one magnetars are known, with five more candidates awaiting confirmation. Examples of known magnetars include:
- SGR 1806-20, located 50,000 light-years from Earth on the far side of our Milky Way galaxy in the constellation of Sagittarius.
- SGR 1900+14, located 20,000 light-years away in the constellation Aquila. After a long period of low emissions (significant bursts only in 1979 and 1993) it became active in May–August 1998, and a burst detected on August 27, 1998 was of sufficient power to force NEAR Shoemaker to shut down to prevent damage and to saturate instruments on BeppoSAX, WIND and RXTE. On May 29, 2008, NASA's Spitzer telescope discovered a ring of matter around this magnetar. It is thought that this ring formed in the 1998 burst.
- SGR 0501+4516 was discovered on 22 August 2008
- 1E 1048.1−5937, located 9,000 light-years away in the constellation Carina. The original star, from which the magnetar formed, had a mass 30 to 40 times that of the Sun.
- As of September 2008, ESO reports identification of an object which it has initially identified as a magnetar, SWIFT J195509+261406, originally identified by a gamma-ray burst (GRB 070610)
- CXO J164710.2-455216, located in the massive galactic cluster Westerlund 1, which formed from a star with a mass in excess of 40 solar masses.
- SWIFT J1822.3 Star-1606 discovered on 14 July 2012 by Italian and Spanish researchers of CSIC and Catalogna's space studies institute. /This magnetar contrary to previsions has a low external magnetic field.
In a close encounter in 1998, one of them "burped out a flare of deadly gamma rays, unleashing as much energy in 0.2 sec. as the Sun will put out in the next 100,000 years. Luckily, the magnetar was located 20,000 light years away from earth."
A full listing is given in the McGill SGR/AXP Online Catalog.
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