Highly Magnetized Accreting Pulsars: Are There Accreting Magnetars?

Pere Blay,Pablo Reig,Víctor Reglero

doi:10.14311/app.2014.01.0215

Pere Blay, Pablo Reig + Show 1 more

Open Access

https://doi.org/10.14311/app.2014.01.0215

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Abstract

2S 0114+650, GX 301-2, IGR J16358-4726, X Per, 4U 2206+54, SXP 1062, and 3A 1954+319 are thought to possess high magnetic elds. They have recently been named accreting magnetars, or highly magnetized accreting pulsars. In this work their properties are reviewed. Within the context of their observational properties (mainly from INTEGRAL data), and the recent models of accretion onto highly magnetized neutron stars, their similarities and dierences are analyzed. The aim is to find a common framework to understand the evolution (in terms of past and present history) of these sources, and to establish the basis of a possible new kind of accreting sources. Two of these sources, namely X Per and 4U 2206+54, contain a massive main-sequence companion, while the rest are supergiant X-ray binaries or symbiotic systems. The variety of astrophysical scenarios represented by this set is wide, therefore the study of these systems is also important in order to establish commonalities between the dierent types of accreting X-ray pulsars and to study the possible evolutionary links between them.

Highlights

Magnetars are neutron stars with bright persistent Xray emission and spin periods on the order of a few seconds
Magnetars are usually grouped into two subclasses, namely Anomalous X-Ray Pulsars (AXPs) and Soft Gamma-Ray Repeaters (SGRs)
According to the Equation (9) from Finger et al (2010), which relates the magnetic moment of the neutron star with the measured spin-down, we find in IGR J16358-4726 a minimum magnetic moment of μ ∼ 2 × 1032 G cm−3, which implies a magnetic field on the order of or larger than B∼ 1014 G

Summary

Introduction

Magnetars are neutron stars with bright persistent Xray emission (on the order of LX ∼ 1033−36ergs−1) and spin periods on the order of a few seconds They show a very drastic spin period evolution, with large spin period derivatives and a long-term spin down tendency. Despite the small number of systems, the variety of astrophysical scenarios represented by this set is wide, from main sequence accreting binary systems (X Per, SXP 1062 and 4U 2206+54) to supergiants (2S 0114+65 and GX 301-2), and even symbiotic systems (IGR J16358-4726 and 3A 1954+319) In this sense, the study of these systems is important to establish commonalities between the different types of HMXRBs and to study the possible evolutionary links between them. Due to the large inhomogeneity in the energy ranges and sets of data available in the literature, we have started an analysis of these systems by using INTEGRAL/IBIS/ISGRI1 data, setting up common energy ranges, spectral resolutions, and performing a homogeneous timing analysis

The Candidates

Magnetic Field Determination via Spin Period Evolution

Magnetic Field Determination via Cyclotron Resonant Scatering Features

Discussion and Conclusion