黑洞候选体X射线双星Cyg X-1光变曲线的研究

利用Rossi X-ray Timing Explorer(RXTE)卫星从1996年1月到2005年5月的公共资料,研究了黑洞候选体X射线双星Cyg X-1光变曲线的周期性,并且发现了一些有趣的周期特性(T=1．0±0．2天和T=18．0±3．0天)．在硬态时,T=1．0±0．2天和T=18．0±3．0天的周期特性同时出现在它的光变曲线之中,但在软态时仅有T=1．0±0．2天的周期出现．采用一种新的方法(即微分法),同时为了检验微分法的正确性,还利用传统的方法(即快速傅立叶变换和叠加法)分析了相同的资料,并得到了与微分法相同的结果．另外也对Cyg X-1的轨道周期进行了研究,结果发现T=5．6天的轨道周期不仅出现在硬态,同时也出现在软态,只是在硬态时比在软态时明显．     

黑洞候选体X射线双星CygX-1长期谱变化的研究

利用Rossi X-ray Timing Explorer(RXTE)卫星从1996年1月5日到2005年5月1日的all-sky monitor(ASM,1.5-12KeV)资料,详细分析了黑洞候选体X射线双星Cyg X-1在A-band(1.5-3KeV),B-band(3-5KeV)和C-band(5-12KeV)三个能段上光子计数率与谱线硬度比HR2(5-12KeV/3-5KeV)的相关性.利用1天时标的ASM资料研究发现: (1)Cyg X-1处于软态时,在A-band上光子计数率与硬度比HR2呈现反相关性,而在B-band和C-band上呈现正相关性.当该天体处于硬态时,在A、B、C三个能段上光子计数率与硬度比HR2都是反相关的.(2)Cyg X-1处于硬态和软态时,硬度比HR2与HR1都是正相关的.此外,还分析了ASM上"Dwell by Dwell"资料,得到了十分有趣的结果,即: (1)MJD=52600-52760期间(此时Cyg X-1处于硬态),A-band和B-band上的光子计数率与HR2是反相关性的,而在C-band上却呈现出较强的正相关性. (2)硬态时,硬度比HR2与HR1存在明显的反相关性.     

基于Jurkevich法Cyg X-1光变周期特性研究

针对天文观测数据不等间隔的特点,利用Jurkevich方法对黑洞候选体X射线双星Cyg X-1近16年的Rossi X-ray Timing Explorer(RXTE)All-Sky Monitor(ASM)数据进行了频谱分析,并结合Kidger周期存在可信度的判据,发现Cyg X-1存在363±11.5 d的光变周期,但没有发现420 d的光变周期,而且150 d的光变周期可能仅仅是51±1.4 d光变周期的观测表象。     

Cyg X-3X光子场对γ射线的吸收效应

本文详细讨论了X射线双星Cyg X-3 的X光子场对γ射线的吸收效应.计算结果表明:当Cyg x-3 的X光子发射场处于高态时,从致密中子星附近发射的能量为10~2—10~4MeV的γ射线约有60％被其吸收,吸收过程产生的正负电子的逆Compton 散射会使出射能量10—70MeV的γ射线强度平均增加约50％.计算的γ射线能谱与实验观测结果基本相符.     

GRS 1915+105的X射线能谱分析及黑洞自旋测量

GRS 1915+105是银河系内的低质量黑洞X射线双星,其能谱和黑洞自旋已经得到了广泛的研究.自2018年6月开始,其X射线流量下降到了低流量水平,其间偶尔会产生多波段的耀发.利用Insight-HXMT(Insight-Hard X-ray Modulation Telescope,简称为慧眼)卫星在2020年8月30日到2020年10月13日之间对GRS1915+105的观测数据,研究了其能谱特性,发现在此次爆发过程中, X射线能谱可以用一个康普顿化的多温黑体谱很好地拟合.整个爆发的硬度强度图(Hardness-Intensity Diagram, HID)一直处于软态.采用GRS1915+105的最新动力学参数M=12.4_-1.8^+2.0M⊙, i=60°±5°, D=8.6_-1.6^+2.0kpc (M、M⊙、i和D分别表示黑洞质量、太阳质量、盘倾角和距离),得到其无量纲黑洞自旋a*的一个下限a*> 0.9990,确认了GRS 1915+105是一个具有极端自旋的黑洞.考虑本地吸收体的...     

黑洞X射线双星的类氢类氦铁Kα发射线

用径移主导吸积流模型（ADAF）不仅可以成功解释很多低吸积率天体的连续谱辐射，也可以说明X射线波段的谱线发射，而后者目前尚少有讨论。以黑洞X射线双星GX339－4处在低吸积率的宁静态情况为例，计算了它的铁线发射，表明在ADAF情况下的确可以产生足够强的可以在观测上检测的类氢和类氦铁Kα线。     

黑洞X射线双星的类氢类氦铁K_α发射线

用径移主导吸积流模型(ADAF)不仅可以成功解释很多低吸积率天体的连续谱辐射,也可以说明X射线波段的谱线发射,而后者目前尚少有讨论.以黑洞X射线双星GX339-4处在低吸积率的宁静态情况为例,计算了它的铁线发射,表明在ADAF情况下的确可以产生足够强的可以在观测上检测的类氢和类氦铁Kα线.     

黑洞X射线双星的类氢类氦铁Kа发射线

用径移主导吸积流模型(ADAF)不仅可以成功解释很多低吸积率天体的连续谱辐射,也可以说明X射线波段的谱线发射,而后者目前尚少有讨论.以黑洞X射线双星GX339-4处在低吸积率的宁静态情况为例,计算了它的铁线发射,表明在ADAF情况下的确可以产生足够强的可以在观测上检测的类氢和类氦铁Kа线.     

天鹅座X-1硬X射线的能量谱

1985年9月22日,我们用空间硬X射线望远镜HAPI-2,在我国的高空气球上,对天鹅座X-1进行了观测,望远镜几何面积为140cm~2,观测能区20—200keV,空间定向精度±0.2°。获得的硬X射线能谱陡,总辐射能流LX～1.0×1~(37)erg/sec,低于常规态。本文将介绍望远镜的性能和观测过程,能谱分析的结果,并对当时天鹅座X-1可能的“态”进行讨论。     

A Study on the Periodicity of Hardness Ratio of the X-ray Binary Cyg X-1 as a Black Hole Candidate

Using the All-Sky Monitor (ASM, 1.5∼12 keV) data of Rossi X-ray Timing Explorer (RXTE) from January 1996 to October 2011, we have analyzed in detail the power spectrum of the hardness ratio (HR) (5∼12 keV/3∼5 keV) of the X-ray binary Cyg X-1 as a black hole candidate. The results show that the HR exhibits the following periodical variations: (1) During MJD = 50087∼55841, the HR presented the the periods T ≈ 5.6 d, T ≈ 40.0 d, T ≈ 78.4 d, T ≈ 173.8 d, and T ≈ 400/800 d; (2) When Cyg X-1 was in the hard state, the HR exhibited the periods T ≈ 5.6 d, T ≈ 33.7/67.6 d, T ≈ 45.3 d, and T ≈ 165.3 d; (3) When Cyg X-1 was in the soft state, the HR exhibited the periods T ≈ 38.5 d, T ≈ d, and T ≈ 128.3 d. Moreover, using the viscosity theory and Zdziarski accretion disk model, we have made a discussion on the physical mechanism of this kind of periodicity.     

A Study on the Long-term Spectral Variability of the Black-hole Candidate X-ray Binary Cyg X-1

Using the All-Sky Monitor (ASM, 1.5–12–kev) data of Rossi X-ray Timing Explorer (RXTE) from January 1996 to May 2005, we have made a detailed analysis of the correlation between photon-count rate and spectral hardness ratio HR2 (5–12 keV/3–5 keV) of the black-hole candidate X-ray binary Cyg X-1 in 3 energy bands, namely the A-band (1.5–3 keV), B-band (3–5 keV) and Cband (5–12 keV). By the study on the ASM data of 1-day time scale, we find: (1) When Cyg X-1 is in the soft state, the A-band photon-count rate and hardness ratio HR2 exhibit an anticorrelation, but in B-band and C-band there appears the positive correlation. When Cyg X-1 is in hard state, the photon-count rates in the A,B,C bands are all inversely correlated with the hardness ratio HR2; (2) No matter whether Cyg X-1 is in the soft state or the hard state, the hardness ratios HR2 and HR1 are always positively correlated. In addition, we have analyzed the “dwell by dwell” data of the ASM, and obtained the following interesting results: (1) In the period of MJD = 52600–52760 (while Cyg X-1 is in the hard state), the photon-count rates in the A-band and B-band are inversely correlated with HR2, but in the C-band there appears a relatively strong positive correlation; (2) During the hard state, a clear anticorrelation exists between the hardness ratios HR2 and HR1.     

基于Jurkevich法CygX-1光变周期特性研究

针对天文观测数据不等间隔的特点,利用Jurkevich方法对黑洞候选体x射线双星CygX-1近16年的RossiX-rayTimingExplorer（RXTE）All-SkyMonitor（ASM）数据进行了频谱分析,并结合Kidger周期存在可信度的判据,发现CygX-1存在363±11．5d的光变周期,但没有发现420d的光变周期,而且150d的光变周期可能仅仅是51±1．4d光变周期的观测表象。     

CygX-1 X辐射的功率谱

运用自回归功率谱研究CygX－1X辐射的频谱特征,结果显示CygX－1转换态和高／软态时变频谱的连续成分,可以统一由有截断的幂律加噪声成分描述,转换态存在小于3Hz的宽峰结构及准周期振荡（QPO）成分（4－12Hz）,而高／软态完全可由截断幂律谱描述,不存在显著的QPO．截断频率在各态都相当稳定,在不同态的演化与平流为主的吸积流模型（ADAF）预期的情形一致．本文结果表明,自回归功率港分析是研究X射线双星光变特征的一个有效的方法．     

Evidence for a new variability in hard X-ray emission of Cyg X-1

From a systematic analysis of the available balloon data for searching variabilities in the time-scales of days for Cyg X-1, the first evidence for the existence of a distinct phase dependence of intensity at 30 keV, corresponding to a period of 5.6 days, is presented. Additionally, the existence of a two-state X-ray emission at these energies is also indicated. Implications of these variabilities on the existing models of Cyg X-1 are discussed.     

Properties of X-ray shots of Cyg X-1 in high state

Temporal variations in the high-energy radiation of Cyg X-1 can be represented by the properties of its X-ray short bursts (shots). The properties of the X-ray shots of Cyg X-1 have been studied extensively, especially for the Cyg X-1 in its typical low/hard state. In this paper, we study the shot properties when Cyg X-1 is in its high/soft state, using direct superposition of shots and the autocorrelation function. Our result shows that when Cyg X-1 is in the high state, the shot structure is qualitatively similar to that of the low state, and that the full-width at half-maximum (FWHM) of the shot decreases with increasing energy, which is inconsistent with the prediction of the Comptonization model. In addition, the evolution of the shot energy spectrum and the asymmetry of the shot structure can explain the observed time lag in Cyg X-1.     

Cyg X-1高态中短暴性质的研究

CygX-1高能辐射的时变特征可以通过短暴(shot)的性质反映．因此CygX-1的短暴性质，特别是处于低态时的性质曾被广泛研究,利用直接叠加短暴和自相关函数，对CygX-1高态时短暴的性质进行了研究．结果表明，当CygX-1处于高态时，其短暴的结构类似于低态时所具有的性质，短暴的半高宽随能量的增加按指数下降．此结果和康普顿化模型不一致．另外，短暴的能谱演化及结构的非对称性可以解释CygX-1中的时延现象．