SGR 1806-20 about two years after the giant flare: Suzaku, XMM-Newton and INTEGRAL observations

Abstract

In December 2004, the soft gamma-ray repeater SGR 1806-20 emitted the most powerful giant flare ever observed. This probably involved a large-scale rearrangement of the magnetosphere leading to observable variations in the properties of its X-ray emission. Here we present the results of the first Suzaku observation of SGR 1806-20, together with almost simultaneous observations with XMM-Newton and INTEGRAL. The source seems to have reached a state characterized by a flux close to the pre-flare level and by a relatively soft spectrum. Despite this, SGR 1806-20 remained quite active also after the giant flare, allowing us to study several short bursts observed by Suzaku in the 1-100 keV range. We discuss the broad-band spectral properties of SGR 1806-20, covering both persistent and bursting emission, in the context of the magnetar model, and consider its recent theoretical developments.

Accepted for publication in Astronomy & Astrophysics

References in corpus (6)

• Corona of Magnetars
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• Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14
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• XMM-Newton observations of Soft Gamma-ray Repeaters
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• The INTEGRAL view of the pulsating hard X-ray sky: from accreting and transitional millisecond pulsars to rotation-powered pulsars and magnetars
• New candidates for magnetar counterparts from a deep search with the Hubble Space Telescope
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