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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: A review of soft gamma repeaters and anomalous X-ray pulsars is given in this article, which contains a brief historical record of the emergence of these classes of neutron stars, a thorough overview of the observational data, a succinct summary of the magnetar model, and suggested directions for future research in this field.
Abstract: This article is a review of Soft Gamma Repeaters and Anomalous X-ray Pulsars. It contains a brief historical record of the emergence of these classes of neutron stars, a thorough overview of the observational data, a succinct summary of the magnetar model, and suggested directions for future research in this field.
30 citations
TL;DR: In this paper, the conditions for magnetars under which their spindown energy input can behave like the 56Ni nuclear decay energy input were investigated, and it was shown that an initial magnetic field strength within a certain range is sufficient to keep the magnetar energy deposition within a factor of a few of the 56Co decay energy for several hundreds of days.
Abstract: Many Type Ic superluminous supernovae have light-curve decline rates after their luminosity peak which are close to the nuclear decay rate of 56Co, consistent with the interpretation that they are powered by 56Ni and possibly pair-instability supernovae. However, their rise times are typically shorter than those expected from pair-instability supernovae, and Type Ic superluminous supernovae are often suggested to be powered by magnetar spin-down. If magnetar spin-down is actually a major mechanism to power Type Ic superluminous supernovae, it should be able to produce decline rates similar to the 56Co decay rate rather easily. In this study, we investigate the conditions for magnetars under which their spin-down energy input can behave like the 56Ni nuclear decay energy input. We find that an initial magnetic field strength within a certain range is sufficient to keep the magnetar energy deposition within a factor of a few of the 56Co decay energy for several hundreds of days. Magnetar spin-down needs to be by almost pure dipole radiation with the braking index close to 3 to mimic 56Ni in a wide parameter range. Not only late-phase 56Co-decay-like light curves, but also rise time and peak luminosity of most 56Ni-powered light curves can be reproduced by magnetars. Bolometric light curves for more than 700 days are required to distinguish the two energy sources solely by them. We expect that more slowly-declining superluminous supernovae with short rise times should be found if they are mainly powered by magnetar spin-down.
30 citations
TL;DR: In this article, the authors reported the first soft γ-ray repeater like burst observed from the anomalous X-ray pulsar (AXP) 1E 1841-045 associated with the supernova remnant Kes 73, discovered on 2010 May 6 by the Burst Alert Telescope on board the Swift γray observatory.
Abstract: We report the study of the short (32 ms) and first soft γ-ray repeater like burst observed from the anomalous X-ray pulsar (AXP) 1E 1841-045 associated with the supernova remnant Kes 73, discovered on 2010 May 6 by the Burst Alert Telescope on board the Swift γ-ray observatory. The 15-100 keV time-averaged burst spectrum is modeled by a single power law (PL) with a photon index Γ = 3.2+1.8 –1.0 and has a fluence of 1.1+0.4 –0.6 × 10–8 erg cm–2, a luminosity of 2.9+1.1 –1.6 × 1039 erg s–1, and an energy of 7.2+0.4 –0.6 × 1036 erg. The prompt after-burst 0.5-10 keV quiescent spectrum obtained with the Swift X-ray Telescope (XRT) is best fit by an absorbed PL model with Γ = 2.6 ± 0.2 and an unabsorbed flux of 9.1+1.2 –1.4 × 10–11 erg cm–2 s–1. To investigate the pre-burst 0.5-10 keV persistent emission, we analyzed the archival XMM-Newton observations, and the spectra are well fitted by a two-component blackbody plus PL model with a temperature kT = 0.45 ± 0.03 keV, Γ = 1.9 ± 0.2, and an unabsorbed flux of 4.3+0.9 –1.2 × 10–11 erg cm–2 s–1. Comparing the Swift-XRT spectrum with the XMM-Newton spectrum, spectral softening post-burst is evident with a 2.1 times increase in the unabsorbed flux. We discuss the burst activity and the persistent emission properties of AXP 1E 1841-045 in comparison with other magnetars and in the context of the magnetar model.
29 citations
TL;DR: In this article, the authors report on the X-ray monitoring of SGR J1935+2154 from ~3 days prior to ~3 weeks after its reactivation, using Swift, NuSTAR, and NICER.
Abstract: A few years after its discovery as a magnetar, SGR J1935+2154 started a new burst-active phase on 2020 April 27, accompanied by a large enhancement of its X-ray persistent emission. Radio single bursts were detected during this activation, strengthening the connection between magnetars and fast radio bursts. We report on the X-ray monitoring of SGR J1935+2154 from ~3 days prior to ~3 weeks after its reactivation, using Swift, NuSTAR, and NICER. We detected X-ray pulsations in the NICER and NuSTAR observations, and constrained the spin period derivative to |Pdot| < 3e-11 s/s (3 sigma c.l.). The pulse profile showed a variable shape switching between single and double-peaked as a function of time and energy. The pulsed fraction decreased from ~34% to ~11% (5-10 keV) over ~10 days. The X-ray spectrum was well fit by an absorbed blackbody model with temperature decreasing from kT ~ 1.6 to 0.45-0.6 keV, plus a non-thermal component (Gamma ~ 1.2) observed up to ~25 keV with NuSTAR. The 0.3-10 keV X-ray luminosity (at 6.6 kpc) increased in less than four days from ~ 6e33 erg/s to about 3e35 erg/s and then decreased again to 2.5e34 erg/s over the following three weeks of the outburst. We also detected several X-ray bursts, with properties typical of short magnetar bursts.
29 citations
TL;DR: In this article, the authors present the results of the first study of global oscillations of relativistic stars with both elastic crusts and interpenetrating superfluid components and show that the entrainment between the superfluid and the crust nuclei is a key parameter in the problem.
Abstract: We present the results of the first study of global oscillations of relativistic stars with both elastic crusts and interpenetrating superfluid components. For simplicity, we focus on the axial quasi-normal modes. Our results demonstrate that the torsional crust modes are essentially unaffected by the coupling to the gravitational field. This is as expected since these oscillations are known to be weak gravitational-wave sources. In contrast, the presence of a loosely coupled superfluid neutron component in the crust can have a significant effect on the oscillation spectrum. We show that the entrainment between the superfluid and the crust nuclei is a key parameter in the problem. Our analysis highlights the need for a more detailed understanding of the coupled crust-superfluid at the microphysical level. Our numerical results have, even though we have not considered magnetized stars, some relevance for efforts to carry out seismology based on quasi-periodic oscillations observed in the tails of magnetar flares. In particular, we argue that the sensitive dependence on the entrainment may have to be accounted for in attempts to match theoretical models to observational data.
29 citations