XRT image of SGR J1550-5418
Credit: NASA/Swift/Jules Halpern (Columbia Univ.)

Smoke Rings

Flaring stars produce a lot of exciting news - but flaring dead stars are even more exciting. Soft Gamma ray Repeaters are weird neutron stars (a class of superdense objects that are weird enough in their own right) that are the most powerful magnets in the known Universe. Only six such objects are known. The most recently identified is SGR J1550-5418, an object that flares frequently and that is pictured above in an image obtained by the X-ray Telescope (XRT) on the Swift Gamma-ray observtory. During the past two years, astronomers using Swift and the Fermi Gamma-ray Space Telescope have identified pulsing X-ray and gamma-ray signals from this object. SGR J1550-5418 began a series of eruptions on Oct. 3, 2008, then settled down, then roared back to life on Jan. 22 with an intense flaring episode. This flare got the notice of astronomers and the Swift observatory, whose X-ray images showed that the flash of X-rays produced "light echoes" from dust shells in the interstellar medium between the source and earth. The evolution of these dust shells tells astronomers a great deal about the structure of the ISM, and can be used to help determine the distance and ultimately the magnetic field strength of the magnetar.
Published: March 2, 2009



Page Author: Dr. Michael F. Corcoran