Oscillations and Collapses of Proto--Neutron Stars

We examine the oscillation and collapse of a relativistic star, e.g., a proto-neutron star, with an equation of state （EOS） which is Mowly changing as driven by, e.g., losing of thermal energy through radiations. We find that the frequency of the fundamental mode of oscillation （radial） will gradually increase then abruptly drop to zero when the star gets close to the point of instability. We also find that for a wide range of configurations on the unstable branch of equilibrium configurations, the collapse is dominated by one unstable mode.     

OPTICAL SPACE OF THE KERR SOLUTIONS

In this paper, we discuss the optical geometry of the Kerr solutions, and show the embedding diagram at the equator θ=π/2 for the optical space of the Kerr solution with a/M=1. It is noticed that at the equator θ=π/2, the Gaussian curvature K for the ordinary space is negative, and the \stackrel{\sim}{K} for the optical space is positive.     

Nonthermal effect of dilatonic black holes

The quantum nonthermal effect of the spherically symmetric and rotating dilatonic black holes is studied. A crossing of the positive and negative Dirac energy of particles occurs near dilatonic black holes. We find that the dilaton coupling parameter α affects the energy of spontaneous radiant particles. The energy of particles decreases when the coupling parameter α increases.     

匀加速直线运动的Kerr黑洞的非热效应

研究了匀加速直线运动的Kerr黑洞周围时空中的自发辐射.得到了发生自发辐射的能量条件,它不仅依赖于黑洞的角动量和加速度,而且还与黑洞的变化有关 关键词： 动态Kerr黑洞 非热辐射     

Determining the long living quasi-normal modes of relativistic stars

Methods of finding quasi-normal modes of non-rotating relativistic stars have been well established,however,none of the existing treatments which take spacetime and fluid oscillations fully into account can determine modes of long decay time,e.g.,the p and g mode series,or the f modes for stars with low compactness ratio (M/R). In this paper we show how the quasi-normal modes of long lifetime can be determined through refinements of a treatment originally due to Detweiler and Lindblom. The determination of the p mode series has been argued in the literature to have implication on the life time of gravitational wave sources and stellar stability. In this paper we 1) provide detailed steps in our treatment to facilitate future effort in this direction; 2) correct mistakes in the literature on the formulation; and 3) analyse the accuracy of the quasi-normal mode frequencies obtained and the limitations of the treatment.     

轴对称荷电动态黑洞的特征曲面

讨论了轴对称荷电动态黑洞的特征曲面,即类时极限面、表观视界和事件视界-分析了黑洞蒸发或吸收质量,以及黑洞电荷发生变化诸种情况- 关键词：     

Relation of Oscillation Frequency to the Equation of State of Relativistic Stars

We study the dependence of quasi-normal modes of neutron stars on their equation of state （EOS）. We construct neutron star configurations of different EOSs while having the same mass M and radius R, and investigate how their l = 2 fundamental mode frequencies would be different. We find that both the real and imaginary parts of the l = 2 frequencies are related to the r^-1 moment of the configurations.