On the morphology and spectra of the short gamma-ray bursts

Barat, C.; Hayles, R. I.; Hurley, K.; Niel, M.; Védrenne, G.; Zenchenko, V. M.; Estulin, I. V.

doi:10.1086/162557

Cited by 51 publications

(45 citation statements)

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“…The other QPOs lasted much longer (∼90 s), and, similar to the 92.5 Hz QPO of SGR 1806−20, they were present only in a rotational phase interval, the same of the 84 Hz oscillations. In retrospect, it is also likely that the hint for a 43 Hz periodicity seen in the March 1979 flare from SGR 0526−66 [8] was due to the same phenomenon.…”

Section: Quasi Periodic Oscillationsmentioning

confidence: 99%

The strongest cosmic magnets: soft gamma-ray repeaters and anomalous X-ray pulsars

Mereghetti

2008

Astron Astrophys Rev

699

766

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Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.

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Section: Quasi Periodic Oscillationsmentioning

confidence: 99%

The strongest cosmic magnets: soft gamma-ray repeaters and anomalous X-ray pulsars

Mereghetti

2008

Astron Astrophys Rev

699

766

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“…Three of these objects have been seen to produce enormously energetic 'giant flares': SGR 0526-66 (Barat et al 1983), SGR 1900+14 and SGR 1806-20 (Israel et al 2005Strohmayer & Watts 2005;Watts & Strohmayer 2006). In the latter two cases, QPOs were detected in the flare's decaying X-ray tail, between 100 and 400 seconds after the initial burst.…”

Section: Introductionmentioning

confidence: 99%

Stratification, superfluidity and magnetar QPOs

Passamonti

Lander

2012

Monthly Notices of the Royal Astronomical Society

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The violent giant flares of magnetars excite QPOs which persist for hundreds of seconds, as seen in the X-ray tail following the initial burst. Recent studies, based on single-fluid barotropic magnetar models, have suggested that the lower-frequency QPOs correspond to magneto-elastic oscillations of the star. The higher frequencies, however -in particular the strong 625 Hz peak -have proved harder to explain, except as high mode multipoles. In this work we study the time evolutions of nonaxisymmetric oscillations of two-fluid Newtonian magnetars with no crust. We consider models with superfluid neutrons and normal protons, and poloidal and toroidal background field configurations. We show that multi-fluid physics (composition-gradient stratification, entrainment) tends to increase Alfvén mode frequencies significantly from their values in a single-fluid barotropic model. The higher-frequency magnetar QPOs may then be naturally interpreted as Alfvén oscillations of the multi-fluid stellar core. The lower-frequency QPOs are less easily explained within our purely fluid core model, but we discuss the possibility that these are crustal modes.

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“…The initial, hard-spectrum emission lasted for τ spike ∼ 0.15 s (Mazets et al 1979), during which time it showed variability on timescales of order ∼ 10 − 30 ms (Barat et al 1983). …”

Section: Outburst Rise-times and Durationsmentioning

confidence: 99%

Triggers of magnetar outbursts

Duncan

2004

Cosmic Explosions in Three Dimensions

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Abstract. Bright outbursts from Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) are believed to be caused by instabilities in ultramagnetized neutron stars, powered by a decaying magnetic field. It was originally thought that these outbursts were due to reconnection instabilities in the magnetosphere, reached via slow evolution of magnetic footpoints anchored in the crust. Later models considered sudden shifts in the crust's structure. Recent observations of magnetars give evidence that at least some outburst episodes involve rearrangements and/or energy releases within the star. We suggest that bursting episodes in magnetars are episodes of rapid plastic yielding in the crust, which trigger "swarms" of reconnection instabilities in the magnetosphere. Magnetic energy always dominates; elastic energy released within the crust does not generate strong enough Alfvén waves to power outbursts. We discuss the physics of SGR giant flares, and describe recent observations which give useful constraints and clues.

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On the morphology and spectra of the short gamma-ray bursts

Cited by 51 publications

References 0 publications

The strongest cosmic magnets: soft gamma-ray repeaters and anomalous X-ray pulsars

The strongest cosmic magnets: soft gamma-ray repeaters and anomalous X-ray pulsars

Stratification, superfluidity and magnetar QPOs

Triggers of magnetar outbursts

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