Astrophysics of Relativistic Jets

相对论性喷流的天体物理学

基本信息

批准号：
09640323
负责人：
TAKAMURA Fumio
金额：
$ 1.47万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640323/
关键词：
Active Galactic Nuslei Relativistic Jets Electron Positron Pairs Particle Acceleration Accretion Disks Gamma Ray Astronomy Radio Galaxies Black Holes 高エネルギー天文学衝撃波

项目摘要

We have made theoretical investigations on the physical properties and bulk acceleration mechanisms of relativistic jets observed in active galactic nuclei and Galactic black hole candidates.1. For the many blazars which have been observed with ASCA, we estimated physical status of the jets utilizing the data of simultaneous multiwavelength observations and found that the energy density of relativistic electrons is much greater than that of magnetic fields. It is also argued that the jets are mainly composed of electron-positron pairs.2. We quantitatively examined bulk acceleration of jets by radiation fields.We assesed the degree of anisotropy of the radiation field which is required to accelerate jets up to the Lorentz factor of 10 through Thomson scattering.We also examined acceleration by synchrotron absorption and showed that when the electron energy and magnetic field strength take most favorable values, Lorentz factor of 100 can be attained for electron-positron jets. However, resultant kinetic luminosity is limited to less than 1% of the Eddington one owing to the effects of the optical thickness.3. We showed that hot accretion disks can produce incipient jets of electron-positron pairs. We solved electron-positron pair equilibrium in the disk taking account of the effect of pair escape and showed that major part of the dissipated power goes into thermal and kinetic energies of escaping pairs when the accretion rate is near the Eddington one. Pairs are heated by Coulomb collisions with higher temperature ions and are accelerated by their own pressure gradient. This provides a new mechanism of jet formation which is physically connected with the gravitational energy release.

我们已经对在活跃的银河核和银河黑洞候选物中观察到的相对论喷射的物理特性和批量加速机制进行了理论研究。1。对于使用ASCA观察到的许多Blazars，我们利用同时多波长观测的数据估计了喷气机的物理状态，发现相对论电子的能量密度远大于磁场的能量密度。还认为喷气机主要由电子旋律对组成。2。 We quantitatively examined bulk acceleration of jets by radiation fields.We assesed the degree of anisotropy of the radiation field which is required to accelerate jets up to the Lorentz factor of 10 through Thomson scattering.We also examined acceleration by synchrotron absorption and showed that when the electron energy and magnetic field strength take most favorable values, Lorentz factor of 100 can be attained for electron-positron jets.然而，由于光学厚度的影响，最终的动力学光度限制为少于爱丁顿的1％。3。我们表明，热积聚磁盘可以产生电子峰值对的初步喷气机。我们在磁盘中求解了电子 - 峰值对的平衡，以考虑到逃脱的效果，并表明当积聚率在爱丁顿一号附近时，消散功率的主要部分进入了逃脱对的热和动力学能量。对库仑碰撞与温度较高的离子进行加热，并通过其自身的压力梯度加速。这提供了一种新的喷射形成机制，该机制与重力释放物理上有实际连接。