论文标题
在特殊的扭矩逆转和X射线亮度历史悠久的历史上
On the peculiar torque reversals and the X-ray luminosity history of the accretion-powered X-ray pulsar 4U 1626--67
论文作者
论文摘要
我们已经研究了旋转和X射线光度（$ L _ {\ Mathrm {x}} $）观察到过去四十年中4U 1626--67的观测值。已经记录说，来源两次进行了扭矩逆转。我们试图了解是否可以用现有的扭矩模型来解释源的时期导数（$ \ dot {p} $）的偏心符号开关。我们发现，观察到的源属性可以更好地估计，距离接近先前预测的距离范围的下限（$ 5-13 $ kpc）。此外，假设有一个倾斜的旋转器，我们已经考虑了从共旋转半径中的部分积聚/弹射，该半径是带领不同的$ l _ {\ mathrm {x}} $ - $ \ $ \ dot {p} $ profiles，而不是对齐的旋转器案例。我们得出的结论是，倾斜旋转器的假设至少使观察到的X射线光度和4U 1626---67的旋转特性至少最佳地拟合。更重要的是，导致观察到的$ l _ {\ mathrm {x}} $ 4U 1626--67的质量积聚率的估计变化远低于在对齐的旋转器案例中发现的。换句话说，如果不需要对伴侣恒星进行大量修改的质量积聚速率，则可以自然地用倾斜的磁轴和中子星的旋转轴自然地解释了观察到的X射线光度的范围。
We have investigated the rotational and the X-ray luminosity ($L_{\mathrm{x}}$) observations of 4U 1626--67 accumulated during the last four decades. It has been recorded that the source underwent a torque reversal twice. We have tried to understand whether this eccentrical sign-switch of the period derivative ($\dot{P}$) of the source could be accounted for with the existing torque models. We have found that the observed source properties are better estimated with the distances close to the lower limit of the previously predicted distance range ($5-13$ kpc). Furthermore, assuming an inclined rotator, we have considered the partial accretion/ejection from the co-rotation radius that leads different $L_{\mathrm{x}}$-$\dot{P}$ profiles than the aligned rotator cases. We have concluded that the oblique rotator assumption brings at least equally best fitting to the observed X-ray luminosity and the rotational properties of 4U 1626--67. More importantly, the estimated change of the mass accretion rate which causes the change in observed $L_{\mathrm{x}}$ of 4U 1626--67 is much less than that is found in an aligned rotator case. In other words, without the need for a substantial modification of mass accretion rate from the companion star, the range of the observed X-ray luminosity could be explained naturally with an inclined magnetic axis and rotation axis of the neutron star.
