SGR J1550-5418 is a soft gamma repeater (SGR), the sixth to be discovered, located in the constellation Norma. Long known as an X-ray source, it was noticed to have become active on 23 October 2008, and then after a relatively quiescent interval, became much more active on 22 January 2009. It has been observed by the Swift satellite, and by the Fermi Gamma-ray Space Telescope, launched in 2008, as well as in X-ray and radio emission.  It has been observed to emit intense bursts of gamma rays at a rate of up to several per minute. At its estimated distance of 30,000 light years (~10 kpc), the most intense flares equal the total energy emission of the Sun in ~20 years.
The underlying object is believed to be a rotating neutron star, of the type known as magnetars, which have magnetic fields up to 1015 gauss, about 1000 times that of more typical neutron star X-ray sources. See Orders of magnitude (magnetic field) for examples of other magnetic field strengths.
The rotation period, ~2.07 s, is the fastest yet observed for a magnetar.
- SpaceRef news item, 10 February 2009.
- NASA press release from GSFC
- "ESA News Release: Swift, Fermi probe fireworks from flaring gamma-ray star". Spaceflight Now. 10 February 2009. Retrieved 20 May 2015.
- GCN CIRCULAR 8901
- SGR/AXP Online Catalog (An online catalog of AXP properties maintained by the pulsar group at McGill University)
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