Magnetar

About: Magnetar is a research topic. Over the lifetime, 2905 publications have been published within this topic receiving 106806 citations.

Observations of a Possible New Soft Gamma Repeater, SGR 1801–23

Abstract: We report on two 1997 June observations of a soft bursting source whose time histories and energy spectra are consistent with those of the soft gamma repeaters. The source can be localized only to an ≈38 long error box in the direction of the Galactic center, whose area is ≈80 arcmin2. The location of the source, while not consistent with that of any of the four known soft repeaters, is consistent with those of several known and possible supernova remnants.

XMM-Newton view of Swift J1834.9-0846 and its Magnetar Wind Nebula

Abstract: We report on the analysis of two XMM-Newton observations of the recently discovered soft gamma repeater Swift J1834.9–0846, taken in 2005 September and one month after the source went into outburst on 2011 August 7. We performed timing and spectral analyses on the point source as well as on the extended emission. We find that the source period is consistent with an extrapolation of the Chandra ephemeris reported earlier and the spectral properties remained constant. The source luminosity decreased to a level of 1.6 × 10^(34) erg s^(–1) following a decay trend of ∝ t^(–0.5). Our spatial analysis of the source environment revealed the presence of two extended emission regions around the source. The first (region A) is a symmetric ring around the point source, starting at 25" and extending to ~50". We argue that region A is a dust scattering halo. The second (region B) has an asymmetrical shape extending between 50" and 150", and is detected both in the pre- and post-outburst data. We argue that this region is a possible magnetar wind nebula (MWN). The X-ray efficiency of the MWN with respect to the rotation energy loss is substantially higher than those of rotation-powered pulsars: η_X ≡ L_(MWN,0.5-8 keV)/Ė_rot ≈ 0.7. The higher efficiency points to a different energy source for the MWN of Swift J1834.9–0846, most likely bursting activity of the magnetar, powered by its high magnetic field, B = 1.4 × 10^(14) G.

On the braking index of the unusual high-b rotation-powered pulsar psr j1846–0258

Abstract: PSR J1846-0258 is an object which straddles the boundary between magnetars and rotation powered pulsars. Though behaving for many years as a rotation-powered pulsar, in 2006, it exhibited distinctly magnetar-like behavior - emitting several short hard X-ray bursts, and a flux increase. Here we report on 7 years of post-outburst timing observations of PSR J1846-0258 using the Rossi X-ray Timing Explorer and the Swift X-ray Telescope. We measure the braking index over the post-magnetar outburst period to be $n=2.19\pm0.03$. This represents a change of $\Delta n=-0.46\pm0.03$ or a 14.5$\;\sigma$ difference from the pre-outburst braking index of $n=2.65\pm0.01$, which itself was measured over a span of 6.5 yr. So large and long-lived a change to a pulsar braking index is unprecedented and poses a significant challenge to models of pulsar spin-down.

A new analysis of the short-duration, hard-spectrum GRB 051103, a possible extragalactic soft gamma repeater giant flare

Abstract: GRB 051103 is considered to be a candidate soft gamma repeater (SGR) extragalactic giant magnetar flare by virtue of its proximity on the sky to M81/M82, as well as its time history, localization and energy spectrum. We have derived a refined interplanetary network localization for this burst which reduces the size of the error box by over a factor of 2. We examine its time history for evidence of a periodic component, which would be one signature of an SGR giant flare, and conclude that this component is neither detected nor detectable under reasonable assumptions. We analyse the time-resolved energy spectra of this event with improved time and energy resolution, and conclude that although the spectrum is very hard its temporal evolution at late times cannot be determined, which further complicates the giant flare association. We also present new optical observations reaching limiting magnitudes of R > 24.5, about 4-mag deeper than previously reported. In tandem with serendipitous observations of M81 taken immediately before and 1 month after the burst, these place strong constraints on any rapidly variable sources in the region of the refined error ellipse proximate to M81. We do not find any convincing afterglow candidates from either background galaxies or sources in M81, although within the refined error region we do locate two UV bright star-forming regions which may host SGRs. A supernova remnant (SNR) within the error ellipse could provide further support for an SGR giant flare association, but we were unable to identify any SNR within the error ellipse. These data still do not allow strong constraints on the nature of the GRB 051103 progenitor, and suggest that candidate extragalactic SGR giant flares will be difficult, although not impossible, to confirm.

A VLT/FLAMES survey for massive binaries in Westerlund 1 - II. Dynamical constraints on magnetar progenitor masses from the eclipsing binary W13

Abstract: Context. Westerlund 1 is a young, massive Galactic starburst cluster that contains a rich coeval population of Wolf-Rayet stars, hotand cool-phase transitional supergiants, and a magnetar. Aims. We use spectroscopic and photometric observations of the eclipsing double-lined binary W13 to derive dynamical masses for the two components, in order to determine limits for the progenitor masses of the magnetar CXOU J164710.2-455216 and the population of evolved stars in Wd1. Methods. We use eleven epochs of high-resolution VLT/FLAMES spectroscopy to construct a radial velocity curve for W13. R-band photometry is used to constrain the inclination of the system. Results. W13 has an orbital period of 9.2709 ± 0.0015 days and near-contact configuration. The shallow photometric eclipse rules out an inclination greater than 65 ◦ , leading to lower limits for the masses of the emission-line optical primary and supergiant optical –