16 yr OF<i>RXTE</i>MONITORING OF FIVE ANOMALOUS X-RAY PULSARS

Dib, Rim; Kaspi, V. M.

doi:10.1088/0004-637x/784/1/37

Cited by 153 publications

(228 citation statements)

References 66 publications

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“…3) There are also observed glitches without associated outburst activity (see, e.g., . It is worth mentioning that a recent systematic analysis of the glitch-outburst connection in five AXPs by Dib & Kaspi (2014) concluded (amongst other important results): 1) glitches associated and not associated with outbursts or radiative changes show similar timing properties, namely outburst activity is not necessarily associated with large glitches; and 2) all glitches observed point to have their origin in the stellar interior. The second conclusion gives observational support to our theoretical interpretation of glitches as a phenomenon associated to cracking occurring in the NS interior.…”

Section: Glitches and Bursts In Sgrs/axpsmentioning

confidence: 83%

“…The second conclusion gives observational support to our theoretical interpretation of glitches as a phenomenon associated to cracking occurring in the NS interior. Whether a glitch can or not lead to observable radiative changes depends on specific properties of the phenomenon such as the energy budget and the localization of the event in the star's interior (Dib & Kaspi 2014), as well as on the efficiency in converting mechanical energy into radiation. The first two features have been here analyzed through ∆E rot and the parameter η, the latter which defines I glitch , the amount of moment of inertia involved in the glitch.…”

Section: Glitches and Bursts In Sgrs/axpsmentioning

confidence: 99%

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The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Coelho

Cáceres

Lima

et al. 2017

A&A

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Context. Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slow rotating isolated pulsars whose energy reservoir is still matter of debate. Adopting neutron star (NS) fiducial parameters; mass M = 1.4M , radius R = 10 km, and moment of inertia, I = 10 45 g cm 2 , the rotational energy loss,Ė rot , is lower than the observed luminosity (dominated by the X-rays) L X for many of the sources. Aims. We investigate the possibility that some members of this family could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. Methods. We compute the NS mass, radius, moment of inertia and angular momentum from numerical integration of the axisymmetric general relativistic equations of equilibrium. We then compute the entire range of allowed values of the rotational energy loss,Ė rot , for the observed values of rotation period P and spin-down rateṖ. We also estimate the surface magnetic field using a general relativistic model of a rotating magnetic dipole. Results. We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, L X /Ė rot , with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for L X computed in the soft (2-10 keV) X-ray band. We compute the range of NS masses for which L X /Ė rot < 1. We discuss the observed hard X-ray emission in three sources of the group of nine potentially rotation-powered NSs. This additional hard X-ray component dominates over the soft one leading to L X /Ė rot > 1 in two of them. Conclusions. We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2-10 keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give additional support to our results of a natural explanation of these sources in terms of ordinary pulsars. Including the hard X-ray emission observed in three sources of the group of potential rotation-powered NSs, this number of sources with L X /Ė rot < 1 becomes seven. It remains open to verification 1) the accuracy of the estimated distances and 2) the possible contribution of the associated supernova remnants to the hard X-ray emission.

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Section: Glitches and Bursts In Sgrs/axpsmentioning

confidence: 83%

Section: Glitches and Bursts In Sgrs/axpsmentioning

confidence: 99%

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Coelho

Cáceres

Lima

et al. 2017

A&A

View full text Add to dashboard Cite

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“…Glitches in normal pulsars and magnetars are sudden spin-up events [18]. However, a spin-down glitch (i.e.…”

Section: Anti-glitch Anti-correlation Between Radiation and Timingmentioning

confidence: 99%

“…Observationally magnetars are more noisy [18]. Therefore, the braking index of magnetars may be difficult to measure.…”

Section: Two Predictions: Wind Nebula and Braking Indexmentioning

confidence: 99%

Understanding Recent Magnetar Observations from the Magnetospheric Point of View

Tong

2018

Proceedings of the Workshop on Quarks and Compact Stars 2017 (QCS2017)

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The wind braking model and its applications to magnetars are discussed. The decreasing torque of magnetars during outbursts, anti-glitch, and anti-correlations between radiation and timing are understandable in the wind braking model. Recent timing observations of magnetars are also consistent with the previous modeling. A magnetism-powered wind nebula and a braking index smaller than three are the two predictions. Besides isolated magnetars, there may also be accreting magnetars in binary systems and magnetars accreting from fallback disks. Observationally, ultra-luminous X-ray pulsars may be accreting magnetars, while super-slow magnetars may be magnetars with fallback disks in the past. Many works are needed for both isolated magnetars and accreting magnetars.

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“…From observation, AXP/SGRs' X-ray outbursts are sometimes associated with glitches (sudden "spin-up" of the star) [4] , and we could expect that stellar oscillations would be excited after glitches. Therefore, we would like to explore the oscillations' effect on the radio behaviors.…”

Section: Introductionmentioning

confidence: 99%

Preface: The 8th International Symposium on Measurement Techniques for Multiphase Flows

Li¹

2014

AIP Conference Proceedings

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We suggest stellar oscillations are responsible for the strange radio behaviors of Anomalous X-ray pulsars and soft Gamma-ray repeaters (AXP/SGRs), within the framework of both solid quark star model and magnetar model. In solid quark star model, the extra voltage provided by oscillations activates the star from under death line to above death line. In magnetar model, oscillations enlarge the radio beam so that increase the possibility to detect it. Later radio emission decays and vanishes as oscillations damp.

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16 yr OFRXTEMONITORING OF FIVE ANOMALOUS X-RAY PULSARS

Cited by 153 publications

References 66 publications

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

Understanding Recent Magnetar Observations from the Magnetospheric Point of View

Preface: The 8th International Symposium on Measurement Techniques for Multiphase Flows

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