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
Swift or SWIFT most commonly refers to:
* SWIFT, an international organization facilitating transactions between banks
** SWIFT code
* Swift (programming language)
* Swift (bird), a family of birds
It may also refer to:
Organizations
* SWIF ...
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 ray
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...
s 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
A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...
, of the type known as ''
magnetar
A magnetar is a type of neutron star with an extremely powerful magnetic field (~109 to 1011 T, ~1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.Ward; Br ...
s'', which have magnetic fields up to 10
15 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.
[
The first observation of " light echos" from a gamma-ray source, a phenomenon long known for visible stars such as novas, was observed from SGR J1550−5418.
The location of SGR J1550−5418 (aka AXP 1E 1547.0-5408), is RA(J2000) = 15h50m54.11s, Dec(J2000) = −54°18'23.7".SGR/AXP Online Catalog]
(An online catalog of AXP properties maintained by the pulsar group at McGill University)
References
Soft gamma repeaters
Norma (constellation)
Magnetars
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