A thermal wind model for the broad emission line region of quasars
A thermal wind model for the broad emission line region of quasars
复制标题
类星体宽发射线区域的热风模型
DOI：
10.1086/160443
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
W. Christiansen
中科院分区：
文献类型：
--
作者：
R. Weymann;J. Scott;A. Schiano;W. Christiansen
参数进行了总结，假设云引起的广泛的发射线的类星体是由膨胀的热气体的压力和流量的相对论粒子的光度相当于光子的光度流通过这种气体。由此产生的加热和动量沉积产生的跨音速热风的动力学特性进行了详细的计算。这种风加速并限制发射线云，从而产生宽发射线（BEL）轮廓。在另一篇论文中，在比BEL区域大得多的距离（约kpc）处的风的特性被用来解释在某些类星体中观测到的宽吸收线（BAL）的产生。同一组风参数可以解释BEL和BAL区域的属性，并且BEL和BAL区域的物理描述的这种统一是该模式最重要的优点之一。类星体发射线区域的特征尺寸约为1 pc是该模型的一个结果。这个特征的大小取决于光度在这样一种方式，电离参数是大致恒定的，在很宽的范围内的光度。由热韧致辐射引起的X射线亮度约为光学亮度的1%-10%是该模型的另一个结果。计算了在冲压加速度和辐射加速度共同作用下的云运动轨迹。从这些轨迹的发射线配置文件也计算，以及风和云的参数产生的配置文件中公平的协议与观察到的配置文件探索。由于电子散射，风中的不透明性使光学细线的线芯向蓝色移动。这是大致补偿的红斜的光学厚线由于优先发射的光子从背面的云。空快速耗尽由于康普顿损失进行了讨论。«少
Arguments are summarized for supposing that the clouds giving rise to the broad emission lines of QSOs are confined by the pressure of an expanding thermal gas and that a flux of relativistic particles with luminosity comparable to the photon luminosity streams through this gas. The resulting heating and momentum deposition produces a transonic thermal wind whose dynamical properties are calculated in detail. This wind accelerates and confines the emission line clouds, thereby producing the broad emission line (BEL) profiles. In a companion paper, the properties of the wind at much larger distances (approx.kpc) than the BEL region are used to explain the production of the broad absorption lines (BAL) observed in some QSOs. The same set of wind parameters can account for the properties of both the BEL and BAL regions, and this unification in the physical description of the BEL and BAL regions is one of the most important advantages of this model. A characteristic size of approx.1 pc for the QSO emission line region is one consequence of the model. This characteristic size is shown to depend upon luminosity in such a way that the ionization parameter is roughly constant over a wide range of luminosities. Anmore » X-ray luminosity due to thermal bremsstrahlung of approx.1%--10% of the optical luminosity is another consequence of the model. The trajectories of clouds under the combined influence of ram pressure acceleration and radiative acceleration are calculated. From these trajectories emission line profiles are also calculated, as well as the wind and cloud parameters yielding profiles in fair agreement with observed profiles explored. Opacity in the wind due to electron scattering displaces the line cores of optically thin lines to the blue. This is roughly compensated for by the redward skewing of optically thick lines due to preferential emission of photons from the back side of the clouds.void rapid depletion due to Compton losses are discussed.« less