【作者】 黄昌印；

【导师】 汪定雄；

【作者基本信息】 华中科技大学 ， 理论物理， 2007， 硕士

【摘要】 X射线双星和活动星系核中的黑洞在质量上跨越6个量级以上,但近来的一些观测表明它们的许多高能辐射特征存在相似性,例如喷流、X射线准周期震荡(QPO)、高发射率指数、铁Kα线等。对它们的相似性以及各现象之间的相关性研究有利于我们更进一步地认识黑洞的本质。本文主要在包含Blandford-Znajek(BZ)和磁耦合(MC)两种磁场位形的BZMC共存模型的基础上,探讨两种尺度黑洞系统的3:2 QPO与喷流、谱态转变的相关性。本文的工作主要集中于以下几个方面:首先,我们介绍了磁场提取黑洞旋转能量的两种机制:BZ过程和MC过程,用改进的等效电路方法推导出BZ过程和MC过程功率和力矩的统一表达式,建立了黑洞视界面角坐标与盘上的径向坐标之间的磁场映射关系,并在此基础上讨论了BZMC的共存条件。另外我们还讨论了磁场的螺旋不稳定性,发现BZMC共存总是伴随着螺旋不稳定性。其次,我们介绍了以共存模型为基础的双热斑模型,黑洞视界面上非轴对称磁场通过MC过程在吸积盘内区形成的内热斑和螺旋不稳定性在盘外区形成的外热斑,利用内外热斑的开普勒运动频率解释不同尺度黑洞系统的3:2 QPO频率比。拟合了几个黑洞X射线双星和银河系中心黑洞的3:2 QPO对,并解释了它们的3:2 QPO对与喷流的相关性,还提出了用BZMC共存临界线作为黑洞X射线双星谱态转变的喷流线的新想法,定性讨论了来自伴星的吸积等离子体数密度涨落导致的高软态和低硬态之间的转变。最后,我们简要介绍了活动星系核中心黑洞和恒星级黑洞的高发射率指数、铁Kα线、X射线QPO以及各现象之间的相关性。尽管两种尺度的黑洞在质量上相差甚远,但是它们的这些现象十分相似,表明它们有相同的物理起源——吸积黑洞。更多还原

【Abstract】 Recently, some observations indicate that lots of high-energy radiation properties of black holes (BHs) in X-ray binaries and active galactic nuclei (AGN) are similar, such as jets, X-ray quasi-periodic oscillations (QPOs), the high emissivity index, Fe Kαlines, etc, though the masses in these objects span, at least, six orders of magnitude. Studying the similarities and correlations among the different phenomena benefits us to understand the essential of these BH systems of different scales. Correlation between 3:2 QPO pairs and jets of two scales of BH systems is discussed in this thesis based on the coexistence of the Blandford-Znajek (BZ) and magnetic coupling (MC) process model (CEBZMC). The main results are summarized as follows.Firstly, we introduce two mechanisms of extracting BH rotating energy through magnetic field: BZ and MC process. The unified analytical expressions for the BZ and MC powers and torques are derived based on an improved equivalent circuit. A mapping relation between the angular coordinate on the BH horizon and the radial coordinate on the accretion disc is established and then the condition for coexistence of BZ and MC process is discussed. In addition, we discuss the screw instability of magnetic field, and find that the state of CEBZMC always accompanies the screw instability.Secondly, a double-hotspots-model for 3:2 QPO pairs is introduced based on CEBZMC. The hotspot in the inner region of the disc is produced by energy transferred from a spinning BH with non-axisymmetric magnetic field. The outer hotspot is produced due to the screw instability of the magnetic field on the disc. The Keplerian orbit frequency of inner and outer hotspot correspond to the upper and lower frequency of QPO pairs respectively. We fit the 3:2 QPO pairs of several BH X-ray binaries and the galactic center BH, and explain the correlation between their 3:2 QPO pair and the jet. A new idea for interpreting the critical line of CEBZMC as the jet line in the state transition of BH X-ray binaries is proposed. And we discuss the state transition due to the fluctuations of the number densities of the accreting plasma from a companion star.Finally, we briefly discuss the high emissivity index, Fe Kαlines and X-ray QPOs in BHs of AGN and stellar-mass BHs and the correlations among them. The similar phenomena in the BH systems of masses varying in a large scales imply that they arise from the same physical origin, accreting BHs.更多还原