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arXiv 1401.2634astro-ph.HE
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反常X射线脉冲星的新认识

A new look at Anomalous X-ray Pulsars

G. S. Bisnovatyi-Kogan, N. R. Ikhsanov

摘要:

我们探讨了在年轻孤立中子星上的回退磁吸积的情况下解释异常X射线脉冲星(AXP)和软伽马射线中继星(SGR)现象的可能性。在这种情况下,脉冲星的X射线发射是由于物质从围绕其磁层的磁性板层吸积到中子星的表面上而产生的。用这种方法计算的中子星的自旋下降速率与观测值接近。我们表明,这些中子星是相对年轻的,正在经历一个过渡,从螺旋桨状态的吸积状态。伽马射线中的中子星活动与它们的相对年轻有关,并由储存在低质量中子星地壳中的非平衡层中的能量提供。由于中子星地壳中的物质与超重核的混合接近其表面并变得不稳定,因此可以释放这种能量。低密度区的核裂变引发链式反应,导致核爆炸。爆发很可能是由中子星吸积的物质在磁极区域积累的区域中发展的不稳定性引发的。

英文摘要:

We explore a possibility to explain the phenomenon of the Anomalous X-ray Pulsars (AXP) and Soft Gamma-ray Repeaters (SGR) within the scenario of fall-back magnetic accretion onto a young isolated neutron star. The X-ray emission of the pulsar in this case is originated due to accretion of matter onto the surface of the neutron star from the magnetic slab surrounding its magnetosphere. The expected spin-down rate of the neutron star within this approach is close to the observed value. We show that these neutron stars are relatively young and are going through a transition from the propeller state to the accretor state. The pulsars activity in the gamma-rays is connected with their relative youth and is provided by the energy stored in the non-equilibrium layer located in the crust of low-mass neutron stars. This energy can be released due to mixing of matter in the neutron star crust with super heavy nuclei approaching its surface and getting unstable. The nuclei fission in the low-density region initiates chain reactions leading to the nuclear explosion. The outbursts are likely to be triggered by an instability developing in the region where the matter accreted by the neutron star is accumulated at the magnetic pole regions.

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