Radiative Processes in High-temperature Plasma in Galaxy Clusters

我们对星系团中的高温等离子体进行了以下两个课题的研究。(1)星系团中的Sunyaev-Zel'dovich效应星系团中电子的康普顿散射使宇宙微波背景（CMB）辐射谱发生畸变。这种效应被称为热Sunyaev-Zel'dovich （SZ）效应。在本研究中，我们导出了热SZ效应的解析表达式，其中包括1998年的相对论修正。1999年，我们成功地推导出了运动学SZ效应的解析表达式，它对应于星系团的固有运动。我们在推导解析表达式时包括了相对论修正。在2000年，我们获得了CMB光子偏振的解析表达式。并给出了热SZ效应的解析拟合公式。(2)簇内等离子体的热轫致憔悴因子近年来，一些研究小组对簇内等离子体的x射线辐射进行了广泛的观察。簇内等离子体中离子和/或电子对电子的热韧致过程是产生x射线的主要过程。在本研究中，我们对包括相对论修正在内的过程进行了详细的分析。我们还推导了热韧致过程的解析拟合公式。我们现在正在计算团内等离子体的热e-e轫致过程。

We have studied the following two subjects for the high-temperature plasmas in the galaxy clusters.(1) Sunyaev-Zel'dovich Effect in the Clusters of GalaxiesThe cosmic microwave background (CMB) radiation spectrum is distorted by the Compton scattering of the electrons in the clusters of galaxies. This effect is called as the thermal Sunyaev-Zel'dovich (SZ) effect. In the present study we have derived analytic expressions for the thermal SZ effect including the relativistic corrections in 1998. In 1999 we have succeeded in deriving an analytic expression for the kinematic SZ effect, which corresponds to the proper motion of the clusters of galaxies. We have included the relativistic corrections in deriving the analytic expression. In 2000 we have obtained the analytic expression for the polarization of the CMB photons. We have also given analytic fitting formula for the thermal SZ effect.(2) Thermal Bremsstrahlung Gaunt Factor for the Intracluster PlasmaRecently X-ray radiations from the intracluster plasmas have been observed extensively by several groups. The thermal bremsstrahlung processes of the electons by ions and/or electrons in the intracluster plasmas are the main processes for producing the X-rays. In the present study we have performed the detailed analysis for the processes including the relativistic corrections. We have also derived analytic fitting formulae for the thermal bremsstrahlung processes. We are now in progress in calculating the thermal e-e bremsstrahlung process in the intracluster plasma.