论文标题
在消失的轨道X射线变异性上,黯淡的二进制毫秒脉冲星47 tuc w
On the vanishing orbital X-ray variability of the eclipsing binary millisecond pulsar 47 Tuc W
论文作者
论文摘要
由于我们不断变化的脉冲风(IBS)观点,X射线发射(IBS)在脉冲星风与恒星风中与同伴的恒星风之间的视野不断变化,因此红back毫秒脉冲星(MSP)通常在其X射线发射中显示出明显的轨道变异性。一些红back(“过渡” MSP)显示了其多波长特性的巨大变化,表明从无线电脉冲星状态到增生驱动状态的过渡。 REDBECK MSP 47 TUC W显示了2002年Chandra ACIS-S观察结果中明显的X射线轨道变异性,在2005 - 06年的Chandra HRC-S观测值中无法检测到,这表明它可能已经经历了国家过渡。但是,2014 - 15年度47 TUC的Chandra观察结果与2002年相似。我们用X射线频谱的两个组件(来自pulsar的软X射线的两个组成部分)解释了与这些时期的不同X射线光曲线(来自IBS的pulsar soft X射线,来自IBS的硬X射线),以及X-Rays的不同启示仪。但是,当我们将最佳拟合光谱与HRC响应文件使用HRC光曲线建模时,我们期望比2005-06 Chandra数据中观察到的更明显和更短的倾角。这表明系统的IBS发生了内在的变化。我们使用ICARUS出色的建模软件,包括IBS的加热计算,对47 TUC W的X射线,光学和UV灯库进行建模。我们最合适的参数指向高空系统(I〜60 ver),这主要由脉冲辐射加热,由IBS辐射,并由伴侣挥舞。
Redback millisecond pulsars (MSPs) typically show pronounced orbital variability in their X-ray emission due to our changing view of the intrabinary shock (IBS) between the pulsar wind and stellar wind from the companion. Some redbacks ("transitional" MSPs) have shown dramatic changes in their multiwavelength properties, indicating a transition from a radio pulsar state to an accretion-powered state. The redback MSP 47 Tuc W showed clear X-ray orbital variability in the Chandra ACIS-S observations in 2002, which were not detectable in the longer Chandra HRC-S observations in 2005-06, suggesting that it might have undergone a state transition. However, the Chandra observations of 47 Tuc in 2014-15 show similar X-ray orbital variability as in 2002. We explain the different X-ray light-curves from these epochs in terms of two components of the X-ray spectrum (soft X-rays from the pulsar, vs. harder X-rays from the IBS), and different sensitivities of the X-ray instruments observing in each epoch. However, when we use our best-fit spectra with HRC response files to model the HRC light-curve, we expect a more significant and shorter dip than that observed in the 2005-06 Chandra data. This suggests an intrinsic change in the IBS of the system. We use the ICARUS stellar modelling software, including calculations of heating by an IBS, to model the X-ray, optical, and UV light-curves of 47 Tuc W. Our best-fitting parameters point towards a high-inclination system (i~60 deg), which is primarily heated by the pulsar radiation, with an IBS dominated by the companion wind momentum.