论文标题
BE/X射线二进制文件中的快速时间光学变异性。脉动和旋转
Fast time optical variability in Be/X-ray binaries. Pulsation and rotation
论文作者
论文摘要
当频率范围0.1-12 d $^{ - 1} $时，经典的恒星，无论光谱子类型如何，都显示多重光调制。这种行为归因于非义脉冲和/或旋转恒星的行为。这项工作的主要目的是研究光学对应物的快速光度变异性为/X射线二进制文件，并将这种变异性的一般模式与经典BE恒星的银河群体进行比较。我们用苔丝分析了21个来源。还针对15个来源进行了使用两个地面望远镜的高效光度表。在频率分析中采用了标准的傅立叶分析和最小二乘拟合方法。在基于地面的观测值中，所有来源均表现出强度变化为0.01-0.06 mag，在苔丝观测中的通量最高5％。这种可变性将自己表现为频率范围0.2-12 d $^{ - 1} $的多周期信号。我们发现，在BE/X射线二进制中，BE恒星的可变性模式与经典早期型BE恒星的变异性在周期图的一般形状上是一致的。基于周期图中的一般形状和峰值，BE/X射线二进制文件可以分为不同类型。最常见的情况是存在紧密间隔频率的组（67％），其次是表现出孤立信号的来源（18％）。其余类型的来源显示频谱，其特征是随机变异性和高频峰的混合模式。这项研究表明，短期光学光度变异性是非常常见的，即使不是无处不在的，它与BE/X射线二进制中的光学伴侣固有的特征。这种变异性主要归因于起源于恒星内部的脉动。
Classical Be stars, regardless of spectral subtype, display multiperiodic light modulations in the frequency range 0.1-12 d$^{-1}$, when observed with high-cadence and long duration. This behaviour is attributed to non-radial pulsations and/or rotation of the Be star. The main goal of this work is to investigate the fast photometric variability of the optical counterparts to Be/X-ray binaries and compare the general patterns of such variability with the Galactic population of classical Be stars. We analyzed 21 sources with TESS. High-cadence photometry with two ground-based telescopes was also performed for 15 sources. Standard Fourier analysis and least-squares fitting methods were employed in the frequency analysis. All sources exhibit intra-night light variations with intensity variations of 0.01-0.06 mag in the ground-based observations and up to 5% in flux in TESS observations. This variability manifests itself as multi-periodic signals in the frequency range 0.2-12 d$^{-1}$. We find that the patterns of variability of the Be stars in Be/X-ray binaries agree with that of classical early-type Be stars in terms of the general shape of the periodograms. Based on the general shape and number of peaks in the periodograms, Be/X-ray binaries can be classified into different types. The most common case is the presence of groups of closely-spaced frequencies (67%), followed by sources that exhibit isolated signals (18%). The remaining type of sources displays frequency spectra characterized by a mixed pattern of stochastic variability and high-frequency peaks. This study reveals that short-term optical photometric variability is a very common, if not ubiquitous, feature intrinsic to the Be optical companions in Be/X-ray binaries. This variability is mainly attributed to pulsations that originate in the stellar interior.
