SGR J1550-5418

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SGR J1550-5418 is a soft gamma repeater (SGR), the sixth[citation needed] 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. [1][2] 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.[3]

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.[3]

The first observation of "Light echos" from a gamma-ray source, a phenomenon long known for visible stars such as novas, have been observed from SGR J1550-5418.

The location of SGR J1550-5418 (aka AXP 1E 1547.0-5408),[4] is RA(J2000) = 15h50m54.11s, Dec(J2000) = -54°18´23.7´´.[5]


  1. ^ SpaceRef news item, 10 February 2009.
  2. ^ NASA press release from GSFC
  3. ^ a b "ESA News Release: Swift, Fermi probe fireworks from flaring gamma-ray star". Spaceflight Now. 10 February 2009. Retrieved 20 May 2015. 
  4. ^ GCN CIRCULAR 8901
  5. ^ SGR/AXP Online Catalog (An online catalog of AXP properties maintained by the pulsar group at McGill University)

Coordinates: Sky map 15h 50m 54.11s, −54° 18′ 23.7″