Unveiling Soft Gamma-Ray Repeaters with INTEGRAL

Abstract

Thanks to INTEGRAL's long exposures of the Galactic Plane, the two brightest Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR 1900+14, have been monitored and studied in detail for the first time at hard-X/soft gamma rays. This has produced a wealth of new scientific results, which we will review here. Since SGR 1806-20 was particularly active during the last two years, more than 300 short bursts have been observed with INTEGRAL. and their characteristics have been studied with unprecedented sensitivity in the 15-200 keV range. A hardness-intensity anticorrelation within the bursts has been discovered and the overall Number-Intensity distribution of the bursts has been determined. In addition, a particularly active state, during which ~100 bursts were emitted in ~10 minutes, has been observed on October 5 2004, indicating that the source activity was rapidly increasing. This eventually led to the Giant Flare of December 27th 2004, for which a possible soft gamma-ray (>80 keV) early afterglow has been detected. The deep observations allowed us to discover the persistent emission in hard X-rays (20-150 keV) from 1806-20 and 1900+14, the latter being in a quiescent state, and to directly compare the spectral characteristics of all Magnetars (two SGRs and three Anomalous X-ray Pulsars) detected with INTEGRAL.

8 pages, 7 figures, Presented at the conference "Isolated Neutron Stars: from the Surface to the Interior", London, UK, 24-28 April 2006

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Cited by in corpus (9)

• The Birthrate of Magnetars
• Soft and Hard X-Ray Emissions from the Anomalous X-ray Pulsar 4U 0142+61 Observed with Suzaku
• Magnetar Giant Flares --- Flux Rope Eruptions in Multipolar Magnetospheric Magnetic Fields
• An MHD Model For Magnetar Giant Flares
• Long term hard X-ray variability of the anomalous X-ray pulsar 1RXS J170849.0-400910 discovered with INTEGRAL
• Magnetar Giant Flares and Their Precursors --- Flux Rope Eruptions with Current Sheets
• Extended VHE gamma-ray emission towards SGR1806-20, LBV1806-20, and stellar cluster Cl*1806-20
• Magnetar Giant Flares in Multipolar Magnetic Fields --- II. Flux Rope Eruptions With Current Sheets
• Magnetar Giant Flares in Multipolar Magnetic Fields --- I. Fully and Partially Open Eruptions of Flux Ropes