Universe  ID: 11713

Fermi Finds Hints of Starquakes in Magnetar 'Storm'

Astronomers analyzing data acquired by NASA's Fermi Gamma-ray Space Telescope during a rapid-fire "storm" of high-energy blasts in 2009 have discovered underlying signals related to seismic waves rippling throughout the host neutron star.

The burst storm came from SGR J1550−5418, a neutron star with a super-strong magnetic field, also known as a magnetar. Located about 15,000 light-years away in the constellation Norma, the magnetar was quiet until October 2008, when it entered a period of eruptive activity that ended in April 2009.

At times, the object produced hundreds of bursts in as little as 20 minutes, and the most intense explosions emitted more total energy than the sun does in 20 years. High-energy instruments on many spacecraft, including NASA's Swift and Rossi X-ray Timing Explorer, detected hundreds of gamma-ray and X-ray blasts.

An examination of 263 individual bursts detected by Fermi's Gamma-ray Burst Monitor confirms vibrations in the frequency ranges previously only seen in rare giant flares from magnetars. Astronomers suspect these are twisting oscillations of the star where the crust and the core, bound by the magnetic field, vibrate together. In addition, a single burst showed an oscillation at a frequency never seen before and which scientists still do not understand.

While there are many efforts to describe the interiors of neutron stars, scientists lack enough observational detail to choose between differing models. Neutron stars reach densities far beyond the reach of laboratories and their interiors may exceed the density of an atomic nucleus by as much as 10 times. Knowing more about how bursts shake up these stars will give theorists an important new window into understanding their internal structure.
Magnetar Burst with Torsional Waves
Magnetar Burst
Unlabled still of Fermi here  


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Astrophysics Stills

SVS >> Neutron Star
SVS >> X-ray
GCMD >> Earth Science >> Spectral/Engineering >> Gamma Ray
SVS >> Astrophysics
SVS >> Space
SVS >> Swift
SVS >> Fermi
SVS >> Magnetar
SVS >> Star
NASA Science >> Universe

GCMD keywords can be found on the Internet with the following citation: Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version