论文标题
白色矮人脉冲星AR天蝎座的长期光度监测和光谱
Long-term photometric monitoring and spectroscopy of the white dwarf pulsar AR Scorpii
论文作者
论文摘要
AR Scorpii（AR SCO）是迄今为止唯一已知的无线电脉冲白色矮人。它显示了从无线电延伸到X射线的宽带频谱，仅由系统组件的热发射无法解释其发光度，而是通过由白矮人的旋转驱动的同步加速器发射来解释的。我们分析了NTT/UltraCAM，TNT/Ultraspec和GTC/Hipercam高速光度数据的AR SCO跨度跨度将近7年，并获得了自旋频率衍生物的精确估计，如今已确认具有50 sigma的显着性。使用档案光度法，我们表明，自2005年以来，P/PDOT = 5.6E6年的旋转速率一直保持恒定。以及采用用于先前估计的脉冲 - 偏置时间拟合方法，我们还首次通过传统的傅立叶分析找到了一致的值。此外，我们通过WHT/ISIS和VLT/X-Shooter获得了光学时间分辨光谱。我们首次为该系统进行了调制多普勒断层扫描，找到了在轨道时期调节发射的证据。我们还估计了M-warf的预计旋转速度是轨道周期的函数，发现它必须接近Roche Lobe填充。我们的发现为建模这个独特的系统提供了进一步的限制。
AR Scorpii (AR Sco) is the only radio-pulsing white dwarf known to date. It shows a broad-band spectrum extending from radio to X-rays whose luminosity cannot be explained by thermal emission from the system components alone, and is instead explained through synchrotron emission powered by the spin-down of the white dwarf. We analysed NTT/ULTRACAM, TNT/ULTRASPEC, and GTC/HiPERCAM high-speed photometric data for AR Sco spanning almost seven years and obtained a precise estimate of the spin frequency derivative, now confirmed with 50-sigma significance. Using archival photometry, we show that the spin down rate of P/Pdot = 5.6e6 years has remained constant since 2005. As well as employing the method of pulse-arrival time fitting used for previous estimates, we also found a consistent value via traditional Fourier analysis for the first time. In addition, we obtained optical time-resolved spectra with WHT/ISIS and VLT/X-shooter. We performed modulated Doppler tomography for the first time for the system, finding evidence of emission modulated on the orbital period. We have also estimated the projected rotational velocity of the M-dwarf as a function of orbital period and found that it must be close to Roche lobe filling. Our findings provide further constraints for modelling this unique system.
