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Magnetar
About: Magnetar is a research topic. Over the lifetime, 2905 publications have been published within this topic receiving 106806 citations.
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TL;DR: In this article, the mean field is generated in the neutron-finger unstable region where the Rossby number is ∼ 1 and mean-field dynamo is efficient, which can lead to the formation of three different types of pulsars.
Abstract: We discuss the mean-field dynamo action in protoneutron stars that are subject to instabilities during the early evolutionary phase. The mean field is generated in the neutron-finger unstable region where the Rossby number is ∼ 1 and mean-field dynamo is efficient. Depending on the rotation rate, the mean-field dynamo can lead to the formation of three different types of pulsars. If the initial period of the protoneutron star is short, then the generated large-scale field is very strong (${>} 3 \times 10^{13}$ G) and exceeds the small-scale field at the neutron star surface. If rotation is moderate, then the pulsars are formed with more or less standard dipole fields (${<} 3 \times 10^{13}$ G) but with surface small-scale magnetic fields stronger than the dipole field. If rotation is very slow, then the mean-field dynamo does not operate, and the neutron star has no global field. Nevertheless, strong small-scale fields are generated in such pulsars, and they can manifest themselves as objects with very low spin-down rate but with a strong magnetic field inferred from the spectral features.
61 citations
01 Sep 2006
61 citations
TL;DR: In this article, the authors reported the discovery of a 4.5μm counterpart to the anomalous X-ray pulsar (magnetar) 1E 2259+586 with the Spitzer Space Telescope.
Abstract: We report the discovery of a 4.5μm counterpart to the anomalous X-ray pulsar (magnetar) 1E 2259+586 with
the Spitzer Space Telescope. The mid-infrared flux density is 6.3 ± 1.0μJy at 4.5μm and <20 μJy (at 95%
confidence) at 8μm, or 0.02% of the 2–10 keV X-ray flux (corrected for extinction). Combining our Spitzer
measurements with previously published near-infrared data, we show that the overall infrared emission from 1E
2259+586 is qualitatively similar to that from the magnetar 4U 0142+61. Therefore, the passive X-ray-heated dust
disk model originally developed for 4U 0142+61 might also apply to 1E 2259+586. However, the IR data from
this source can also be fitted by a simple power-law spectrum as might be expected from magnetospheric emission.
61 citations
TL;DR: In this article, numerical equilibrium models of magnetized neutron stars endowed with a confined two-isted magnetosphere were investigated, solving the general relativistic Grad-Shafranov equation both in t he interior and in the exterior of the compact object.
Abstract: Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars are extreme manifestations of the most magnetized neutron stars: magnetars. The phenomenology of their emission and spectral properties strongly support the idea that the magnetospheres of these astrophysical objects are tightly twisted in the vicinity of the star. Previous stu dies on equilibrium configurations have so far focused on either the internal or the external magnetic field configuration, without considering a real coupling between the two fields. Here we in vestigate numerical equilibrium models of magnetized neutron stars endowed with a confined tw isted magnetosphere, solving the general relativistic Grad-Shafranov equation both in t he interior and in the exterior of the compact object. A comprehensive study of the parameters space is provided, to investigate the effects of different current distributions on the overall magnetic field st ructure.
61 citations
TL;DR: In 1998 June-July, the Konus-Wind burst spectrometer observed a series of bursts from the new soft gamma repeater SGR 1627-41 as discussed by the authors.
Abstract: In 1998 June-July, the Konus-Wind burst spectrometer observed a series of bursts from the new soft gamma repeater SGR 1627-41. Time histories and energy spectra of the bursts have been studied, revealing fluences and peak fluxes in the ranges 3 × 10-7 to 7.5 × 10-6 ergs cm-2 and 10-5 to 10-4 ergs cm-2 s-1, respectively. One event, 18 June 6153.5 s UT, stands out dramatically from this series. Its fluence is ~7 × 10-4 ergs cm-2, and its peak flux is ~2 × 10-2 ergs cm-2 s-1. These values from a source at a distance of 5.8 kpc yield an energy output of ~3 × 1042 ergs and a maximum luminosity of ~8 × 1043 ergs s-1 for isotropic emission, similar to the values for the famous 1979 March 5 and 1998 August 27 events. In terms of energy, this event is another giant outburst seen in a third soft gamma repeater! However, this very energetic burst differs significantly from the other giant outbursts. It exhibits no separate initial pulse with a fast rise time, no extended tail, and no pulsations. It is rather similar to ordinary repeated bursts, but is a few hundred times stronger in intensity. According to the magnetar model by Thompson & Duncan, such a burst may be initiated by a strong starquake when a crust fracture propagates over the whole surface of a neutron star.
61 citations