Radial Velocity and Light Curves Analysis of the Contact Binary V1073 Cygni

In this study complete BV light curves of the W Ursae Majoris binary V1073 Cygni obtained in 2005 are presented. We have used the spectroscopic data of V1073 Cyg obtained by Ahn et al. (1992) for analysis. The analysis of radial velocity and light curves was made with Wilson} program (1998) and the geometric and physical elements} of the system were derived. By searching the simultaneous} solutions of the system, we have determined the masses and radii of the components: 1.64M_⊙, 2.275R_⊙ for the primary component and 0.55M_⊙, 1.397R_⊙ for the secondary component respectively. The effective temperature of 6494 ± 53 K for the secondary component was also estimated.     

The Masses of Black Holes in X-ray Binary Systems

Recent results concerning the determination of the masses of eleven black hole candidates in X-ray binary systems are summarized. It is very significant that there are no pulsars or X-ray bursters of the first kind among the eleven known massive (mx > 3M) X-ray sources in close binary systems.     

Radial Velocity and Light Curves Analysis of the Contact Binary V839 Ophiuchi

Complete UBV light curves of the W Ursae Majoris binary V839 Ophobtained in the year 2000 are presented. The available spectroscopic data of V839 Oph is new and we used the first radial velocity data of this system obtained by Rucinski and Lu (1999)for analysis. The radial velocity and light curves analysis was made with the latest version of Wilson programme (1998) and the geometric and physical elements of the system are derived. By searching the simultaneous solutions of the system we have determined the masses and radii of the components: 1.61M _⊙and 1.49402R _⊙ for the primary component; 0.50M _⊙and 0.90147R _⊙ for the secondary component. We estimate deffective temperatures of 6650±18 (K) for the primary and6554±15 (K) for the secondary component. This revised version was published online in July 2006 with corrections to the Cover Date.     

基于SVM的食双星光变曲线自动分类算法

提出一种基于机器学习的食双星光变曲线自动分类算法。首先对数据进行预处理,将食双星光变曲线数据归一化,并通过滤波/插值降低噪声;其次使用快速傅里叶变换提取频率信号作为特征向量;最后利用特征向量训练支持向量机获得自动分类模型。使用Python实现算法并抓取CALEB和GCVS数据验证,分析特征向量、支持向量机核函数与惩罚系数对分类正确率的影响,优化后所得分类模型正确率达到92.8%(训练集)和89.0%(测试集),最后使用所得分类模型对第3方数据进行分类,正确率为88.8%,结果证明提出的分类算法的有效性。     

Formation and Evolution of Intermediate Mass Black Hole X-Ray Binaries

The evolution of young (≲ 10 Myr) star clusters with a density exceeding about 10⁵ star pc⁻³ are strongly affected by physical stellar collisions during their early lifetime. In such environments the same star may participate in several tens to hundreds of collisions ultimately leading to the collapse of the star to a black hole of intermediate mass. At later time, the black hole may acquire a companion star by tidal capture or by dynamical – three-body – capture. When the captured star evolves it starts to fill its Roche-lobe and transfers mass to its accompanying black hole. This then leads to a bright phase of X-ray emission, which lasts for the remaining main-sequence lifetime of the donor. If the star captured by the intermediate mass black hole is relatively low mass ≲ 2 M⊙) the binary will also be visible as a bright source in gravitational waves. Based on empirical models we argue that, for as long as the donor remains on the main sequence, the source will be ultraluminous L_x >rsim 10⁴⁰ ergs^-1 for about a week every few month. When the donor star is more massive >15 M⊙, or evolved off the main sequence the bright time is longer, but the total accretion phase lasts much shorter.     

射电选和X射线选BL Lacertae天体的射电性质

收集了射电选和X射线选BL Lac天体的射电数据(包括核和延展光度), 并计算了它们的核主导系数R.研究显示: 射电选BL Lac(RBLs)天体的总射电光度是X射线选BL Lac(XBLs)天体的2个量级.详细分析得到这种差别主要是来自于核光度的差别因为延展光度差别只有1个量级.研究RBLs和XBLs的核(延展元)光度与核主导系数之间的关系, 发现延展元光度与核主导系数负相关, 而核(总)光度几乎与核主导系数没有相关.     

几何薄光学厚吸积盘谱线轮廓及成像研究

假设位于黑洞赤道面上做圆形轨道运动的吸积盘是几何薄、光学厚的.利用光子追踪法计算在Kerr度规下的光子运动轨迹,通过数值计算研究薄吸积盘的相对论谱线轮廓及成像.在大角度观测时,吸积盘下表面的光子对谱线轮廓及成像的影响是显著的.     

潮汐效应、系统自转效应对双星物质交换过程的影响

现今双星演化理论中,以子星的半径等于临界洛希瓣半径,作为双星中发生物质交换过程的判据,仅仅是一个为了将三维计算简化为一维计算而引入的近似判据．它在理论上是不严格的．本文给出了一个理论严格而又能一维计算的判据．并用新的判据和用子星半径等于临界洛希瓣半径的判据,对一个由９Ｍ和６Ｍ恒星组成的双星系统,进行了情况Ａ的演化计算（即物质交换过程发生在主星中心氢燃烧阶段）．结果证明,用新的判据时,双星中发生物质交换过程的起始时间提前,快速物质交换过程变短,平均物质交换率增大,但慢速物质交换过程变长．在物质交换过程结束时,主星和次星的质量、双星系统的轨道周期以及主星在赫罗图中的位置,都与采用子星半径等于相应洛希瓣半径作为判据的计算结果明显不同．这说明,发生物质交换过程的判据是否严格,对于双星演化的影响是不可忽略的．     

Influence of the Return Current on the EUV and X-Ray Flare Line Emissions

Electron beams accelerated during solar flares carry electric currents which should be neutralized by so-called return currents. Both the electron beam and return current modify the electron distribution function in the solar transition region and low corona. Thus, they influence the intensities of the spectral lines formed in these layers. Synthetic spectra for the solar flare atmosphere are computed from model conditions and the possibilities of diagnostics of the return current from the EUV and X-ray line spectra are discussed.     

黑洞的搜寻和证认(II):脉冲星-黑洞(PSR-BH)双星系统的研究和搜寻

综述了脉冲星-黑洞（PSR－BH）系统的诞生率理论并指出近期发现该系统的可能性。通过综述和分析脉冲星-中子星（PSR－NS）系统的观测特性,特别是脉冲星精确守时性对精确确定双星轨道参量和验证引力理论的重要意义,推测了PSR－BH系统的可能性质,指出发现PSR-BH系统对黑洞的搜寻和最终证认的重要意义。最后简介目前搜寻PSR-BH系统的现状和我们搜寻短轨道周期脉冲双星的计划。     

星系NGC5018的星族合成研究

利用星团谱样本的星族合成方法,研究了邻近巨椭圆星系NGC5018中的星族成分和其内部的恒星形成历史,给出了星系中不同年龄和金属丰度星族的成分占有比.星族合成结果表明,NGC5018中不仅存在大量金属丰度低的年老恒星成分,而且较年轻的星族成分(T=5×108yr)对星系光度贡献也很重要.星系吞并和相互作用过程可能是触发这些较年轻星族形成的物理原因,椭圆星系内部的恒星形成历史可能是2次爆发或者多次爆发过程.这些结果可以很好地解释NGC5018颜色偏蓝、Mg2谱指数强度偏弱等观测特征.     

双黑洞系统的不同起源及其参数分布

双黑洞组成的近密双星系统并合是激光干涉仪引力波天文台等地基引力波探测器的主要探测对象。随着探测器灵敏度的提高,大量该类信号的探测将成为进一步研究黑洞物理的有效工具。但是目前对双黑洞系统的起源机制和内禀参数分布等物理问题的研究还不够深入,例如由引力波探测得到的黑洞质量分布与X射线双星观测的结果存在较大差异,还未有很好的理论模型可解释该结果。目前普遍认为双黑洞系统主要有两种起源:大质量双星演化机制和动力学起源机制。基于这两类起源的双黑洞系统在质量、自旋分布等方面存在差异。因此可在贝叶斯理论框架下,利用引力波信号携带的波源质量和自旋等信息,推断波源起源,计算不同起源的双黑洞系统所占比例,以及检验质量自旋等参数分布的差异。     

判断分光双星自转同步性方法的理论改进

本文在前文[1]研究的基础上对判断分光双星自转的同步性在理论上做了进一步改进.对双谱分光双星用视向速度曲线的半振幅K_1和K_2代替质量比q.对单谱分光双星除前文给出一种判断同步性方法外又给出两种方法.另外,用改进的公式对6对分光双星的同步性做了计算和判断.最后对所得结果做了讨论并用结束语对此项研究工作做了回顾和展望.     

Future Prospects for Ultra-High Resolution Imaging of Binary Systems at UV and X-ray Wavelengths

UV and X-ray space-based interferometry will open unprecedented possibilities for spectral and spatial studies of a wide range of currently unresolvable interacting systems. Ultra-high angular resolution direct imaging of individual} components and transport processes in interacting binary systems is essential for detailed studies and modeling of accretion and activity. Understanding the mass loss characteristics of both components, and the dynamics of the system as a function of time, will provide key inputs to evolutionary models and will revolutionize our view and understanding of the Universe.     

子载波相位与BOC信号功率谱密度的关系研究

首先介绍了导航信号功率谱密度求解的一种通用方法,基于该方法,经过建模和推导,得到任意相位子载波BOC(二进制偏移载波)信号的功率谱密度显式表达式。通过仿真及分析表明,不同的子载波相位对应的BOC信号功率谱密度存在差别,正是这些差别影响了导航系统的性能,同时也为导航系统的信号体制设计带来了灵活性。文中得到的一些结论,可以给未来的导航信号体制设计中BOC信号子载波相位的选择提供一些借鉴。     

Status of Satellite Orbit Determination and Time Synchronization Technology for Global Navigation Satellite Systems

In the form of satellite ephemerides and clock parameters, the space datum and system time information of one global navigation satellite system (GNSS) is transferred to users. With the continuous updating in the satellite payload such as the high-precision atomic clock, the monitoring and tracking technique such as the inter-satellite link, and in the data processing technique, the accuracy and real-time performance of the satellite ephemeris and clock error products are steadily improved. Starting from December 27th, 2018, the BeiDou Navigation System 3, or BDS-3, has provided the accurate and reliable basic positioning, navigation, and timing (PNT) service for the users in the countries within the “one belt and one road”. This paper has summarized the faced challenges of the precise orbit determination and time synchronization from the regional BDS-2 system to the BDS-3 global system, and the specific solutions at the control segment. In addition, this paper has compared the BDS with other GNSS systems in terms of technical characteristics. Finally, aiming at a higher accuracy and more reliable PNT service, the road map of precise orbit determination and time synchronization technique for the next generation navigation systems is discussed, which will provide a reference for developing the global navigation satellite systems with an even higher accuracy.     

硬X射线成像仪量能器测试系统的设计与实现

硬X射线成像仪(Hard X-ray Imager, HXI)是先进天基太阳天文台(Advanced Space-based Solar Observatory, ASO-S)的3大载荷之一, 其中量能器作为其重要组成部分, 承担着观测30--200keV能段的太阳硬X射线的任务. 在卫星发射之前, 需要开展大量的测试工作, 以确保HXI量能器的各项功能和性能满足设计需求. HXI量能器通道数众多, 内含99个溴化镧探测器, 分别由8块相同的前端电子学板控制. 除了对各个通道的性能进行测试外, 地检系统还需模拟量能器在轨面对不同太阳活动时的运行情况, 对量能器进行全面完备的测试. 此外, 地检系统还需足够稳定, 能满足量能器在单机测试、环境试验、热真空与振动等多个不同测试项目的长时间测试需求. 为此, 设计了地检板与上位机软件, 结合放射源、直流电源、高压模块等组成一套HXI量能器的地检系统, 对8块前端电子学板实现同步配置与管理, 能高效完成指令发送与数据接收, 满足量能器最大数据输出带宽400Mbps的需求. 利用该系统, 在地面完成了HXI量能器的功能、性能验证, 获得了量能器的线性、死时间、能量分辨率等各项性能指标, 为HXI量能器的在轨高性能运行提供了保障.