Accretion Disks with a Cloudy Sky-photon Floater
Accretion Disks with a Cloudy Sky-photon Floater
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带有阴天光子浮子的吸积盘
DOI：
10.1093/pasj/48.1.89
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发表时间：
1996
影响因子：
2.3
通讯作者：
J. Fukue
中科院分区：
文献类型：
--
作者：
J. Fukue
在围绕中心物体的吸积盘上方/下方旋转的物质受到该盘的强辐射场以及该中心物体的重力的影响。我们发现存在一个临界漂浮高度，在该高度，中心物体的垂直重力被来自圆盘的辐射力平衡，材料在那里是光子漂浮的。临界漂浮高度由圆盘有效光度Reff决定，其定义为Reff=(CT/CTT)(MP/m)(Ld/Le)，其中Ct和m分别是材料的横截面和质量，CTT和mp分别是汤姆逊截面和质子质量，Ld和Le分别是圆盘光度和爱丁顿光度。对于较小的ref或较大的r(？z)，临界浮动高度Zf表示为ZF rv 3 rinreff，其中Rin是圆盘的内径。天体物理上重要的一点是，这个临界浮动高度是动态稳定的；因此，受到圆盘辐射场影响的材料，如气云、尘埃或人造物质，会朝着这个浮动高度漂移。这种漂浮的云--光子漂浮物--在圆盘上方/下方部分地遮蔽了圆盘。如果圆盘天空是多云的，观测到的光度就会变得不规则。此外，如果天空多云，由于再处理，发射的光谱将被显著修改。多云的天空也会产生吸收/排放特征。此外，由于来自圆盘的辐射在临界漂浮高度被浮云散射，圆盘看起来好像其厚度已变为ZF。天气环境，如多云或尘土飞扬的天空，会显著改变磁盘的外观。
Materials rotating above/below an accretion disk around a central object suffer from the influence of the strong radiation fields of the disk as well as the gravity of the central object. We find that there exists a critical floating height where the vertical gravity of the central object is balanced by the radiation force from the disk, and the materials are photon-floating there. The critical floating height is detemined by the disk effective luminosity reff, which is defined by reff = (CT/CTT)(mp/m)(Ld/LE), where CT and m are the material cross-section and mass, respectively, CTT and m p the Thomson cross-section and the proton mass, respectively, and Ld and LE the disk luminosity and the Eddington luminosity, respectively. For small r eff or large r (» z) the critical floating height ZF is expressed as ZF rv 3 rinreff, where rin is the inner radius of the disk. The astrophysically important point is that this critical floating height is dynamically stable; hence, materials, such as gas clouds or dust or artificials, suffering from the radiation field of the disk drift toward this floating height. Such floating clouds - photon floaters - above/below the disk partially occults the disk. If the disk sky is cloudy, the observed luminosity becomes irregular. Futhermore, if a cloudy sky is present, the emitted spectrum would be remarkably modified due to reprocessing. A cloudy sky would also produce absorption/emission features. In addition, since the radiation from the disk is scattered by floating clouds at a critical floating height, the disk appears as if its thickness had become ZF. The weather environment, such as a cloudy or dusty sky, changes the disk appearance significantly.