Magnetar

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

A tale of two populations: rotating radio transients and x-ray dim isolated neutron stars

Abstract: We highlight similarities between recently discovered Rotating Radio Transients and X-ray Dim Isolated Neutron Stars. In particular, it is shown that X-ray Dim Isolated Neutron Stars have a birthrate comparable to that of Rotating Radio Transients. On the contrary, magnetars have too low a formation rate to account for the bulk of the radio transient population. The consequences of the recent detection of a thermal X-ray source associated with one of the Rotating Radio Transients on the proposed scenarios for these sources are also discussed.

Deep nustar and swift monitoring observations of the magnetar 1e 1841−045

Abstract: We report on a 350 ks NuSTAR observation of the magnetar 1E 1841–045 taken in 2013 September. During the observation, NuSTAR detected six bursts of short duration, with T90 ≤ 1 s. An elevated level of emission tail is detected after the brightest burst, persisting for ∼1 ks. The emission showed a power-law decay with a temporal index of 0.5 before returning to the persistent emission level. The long observation also provided detailed phaseresolved spectra of the persistent X-ray emission of the source. By comparing the persistent spectrum with that previously reported, we find that the source hard-band emission has been stable for over approximately 10 yr. The persistent hard-X-ray emission is well fitted by a coronal outflow model, where e^± pairs in the magnetosphere upscatter thermal X-rays. Our fit of phase-resolved spectra allowed us to estimate the angle between the rotational and magnetic dipole axes of the magnetar, amag = 0.25, the twisted magnetic flux, 2.5 × 10^(26) G cm^2, and the power released in the twisted magnetosphere, L_j = 6 × 10^(36) erg s^(−1). Assuming this model for the hard-X-ray spectrum, the soft-X-ray component is well fit by a two-blackbody model, with the hotter blackbody consistent with the footprint of the twisted magnetic field lines on the star. We also report on the 3 yr Swift monitoring observations obtained since 2011 July. The soft-X-ray spectrum remained stable during this period, and the timing behavior was noisy, with large timing residuals.

Unusual Burst Emission from the New Soft Gamma Repeater SGR1627-41

Abstract: In June-July,1998 the Konus-Wind burst spectrometer observed a series of bursts from the new soft gamma repeater SGR1627-41. Time histories and energy spectra of the bursts have been studied, revealing fluences and peak fluxes in the ranges of 3x10^{-7} - 7.5x10^{-6} erg cm^{-2} and 10^{-5} - 10^{-4}erg cm^{-2}/s respectively. One event, 18 June 6153.5sUT stands out dramatically from this series. Its fluence is ~7x10^{-4} erg cm^{-2} and peak flux ~2x10^{-2} erg cm^{-2}/s. These values from a source at a distance of 5.8 kpc yield an energy output of ~3x10^{42}erg and maximum luminosity of ~8x10^{43} erg/s, similar to the values for the famous March 5, 1979 and August27,1998 events. In terms of energy, this event is another giant outburst seen in a third SGR! 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 and Duncan (1995) such a burst may be initiated by a strong starquake when a crust fracture propagates over the whole surface of a neutron star.

X-ray spectra from magnetar candidates - III. Fitting SGRs/AXPs soft X-ray emission with non-relativistic Monte Carlo models

Abstract: Within the magnetar scenario, the "twisted magnetosphere" model appears very promising in explaining the persistent X-ray emission from the Soft Gamma Repeaters and the Anomalous X-ray Pulsars (SGRs and AXPs). In the first two papers of the series, we have presented a 3D Monte Carlo code for solving radiation transport as soft, thermal photons emitted by the star surface are resonantly upscattered by the magnetospheric particles. A spectral model archive has been generated and implemented in XSPEC. Here we report on the systematic application of our spectral model to different XMM-Newton and Integral observations of SGRs and AXPs. We find that the synthetic spectra provide a very good fit to the data for the nearly all the source (and source states) we have analyzed.

Hadronic and hybrid stars subject to density dependent magnetic fields

Abstract: In the light of the very massive neutron stars recently detected and the new possible constraints for the radii of these compact objects, we revisit some equations of state obtained for hadronic and hybrid stars under the influence of strong magnetic fields. We present our results for hadronic matter, taking into account the effects of the inclusion of anomalous magnetic moment. Additionally, the case of hybrid stars under the influence of strong magnetic fields is considered. We study the structure of hybrid stars based on the Maxwell condition (without a mixed phase), where the hadron phase is described by the nonlinear Walecka model (NLW) and the quark phase by the Nambu-Jona-Lasinio model (NJL). The mass-radius relations for all cases are calculated and discussed. We show that both hadronic and hybrid stars can bear very high masses and radii, compatible with the recently observed high-mass neutron stars.