In this paper, we attribute high braking indices n > 3 of two magnetars SGR 0501+4516 and 1E 2259+586 to the decrease in their inclination angles using the double magnetic‐dipole model proposed by Hamil et al. (2016). In this model, there are two magnetic moments inside a neutron star—one is generated by the rotation effect of a charged sphere, M₁, and the other is generated by the magnetization of ferromagnetically ordered material, M₂. Our calculations indicate that the magnetic moment M₂ would evolve toward alignment with the spin axis of the two magnetars and cause their magnetic inclination angles to decrease. We also define a ratio η = M₂/M₁, which reflects the magnetization degree, and find that the values of η of the two magnetars are about two orders of magnitude higher than that of rotationally powered pulsar PSR J1640‐4631 with n = 3.15(3), assuming that they have the same rate of decrease in their inclination angles.

中文翻译：

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使用双磁偶极子模型解释SGR 0501 + 4516和1E 2259 + 586磁星的高制动指数

在本文中，我们使用Hamil等人提出的双磁偶极子模型将两个磁星SGR 0501 + 4516和1E 2259 + 586的高制动指数n  > 3归因于其倾斜角的减小。（2016）。在该模型中，中子星内部有两个磁矩-一个是由带电球体M ₁的旋转效应产生的，另一个是由铁磁有序材料M ₂的磁化产生的。我们的计算表明，磁矩M ₂会朝着与两个磁星的自旋轴对齐的方向发展，并使它们的磁倾角减小。我们还定义了一个比率η  =  M₂ /中号₁，它反映了磁化度，并发现的值η两个磁星是大约两个数量级比旋转动力的脉冲星更高PSR J1640-4631与Ñ  = 3.15（3） ，假定它们具有相同的倾斜角度减小率。