论文标题
提议的白色紫外线脉冲星AR天蝎座的旋转率提高了
An Improved Spin-Down Rate for the Proposed White-Dwarf Pulsar AR Scorpii
论文作者
论文摘要
我们分析了来自三个观测值的AR蝎子的快速添加度，涵盖了五个观测季节。我们测量了系统节拍脉冲的到达时间，并使用它们来计算更新的埃弗默斯。估计白矮人旋转率仅为4％。毫无疑问，这些结果证实，白矮人的自旋时期正在以与Stiller等人相一致的速度增加。 （2018）。我们研究了节拍脉冲的颜色指数在轨道上的演变。在整个轨道上，初级脉冲最大值的颜色差异明显变化，峰值在上半部分之后的峰值比在轨道的上半部分更蓝。具体而言，在轨道相0.5时，主脉冲的颜色指数显示出对蓝色指数的非常清晰的不连续性。这支持Potter＆Buckley（2018b）同步发射模型，其中两个发射杆的颜色在颜色上有很大差异。但是，没有看到次级脉冲的颜色的相应跳跃。此外，我们的分析表明，根据二进制轨道阶段的不同，脉冲的到达时间可能会在同时$ u $和$ r $ $ $ $ $ $的光度法中差异多达6s。如果未校正，则这种依赖于波长的时序偏移可能会导致对自旋周期衍生物的错误测量，尤其是在异质数据集中。
We analyze rapid-cadence, multiwavelength photometry of AR Scorpii from three observatories, covering five observing seasons. We measure the arrival times of the system's beat pulses and use them to compute an updated ephemeris. The white dwarf spin-down rate is estimated with an uncertainty of only 4%. These results confirm, beyond any doubt, that the white dwarf's spin period is increasing at the rate consistent with by that of Stiller et al. (2018). We study the evolution of the beat pulse's color index across the orbit. The color of the primary pulse maxima varies significantly across the orbit, with the peaks being bluer after superior conjunction than in the first half of the orbit. Specifically, at orbital phase 0.5, the color index of the primary pulse shows a very sharp discontinuity towards bluer indices. This supports the Potter & Buckley (2018b) synchrotron emission model where the two emitting poles differ significantly in color. However, no corresponding jump in the color of the secondary pulses is seen. Furthermore, our analysis reveals that the arrival times of the pulses can differ by as much as 6s in simultaneous $u$ and $r$ photometry, depending on the binary orbital phase. If left uncorrected, this wavelength-dependent timing offset could lead to erroneous measurements of the spin-period derivative, particularly with heterogeneous datasets.
