摘要
利用简单的torns束流模型定量计算Seyfert2型星系的偏振度和散射流量的角分布,在“一次电子散射”的假定下,得到偏振度约为10%~80%.而偏振流量的角分布与torns半张角θc和观测角φo都有关.特别是当φo 55°时,观测方向的流量和总的散射流量的比值为一定值(0.16).用这种纯电子散射模型来解释NGC1068的光谱偏振更为合适.对于其它一些具有低的偏振度的Seyfert2星系,尘埃的作用则不能忽略.
We discuss the simple torns beaming/scattering model for Type-2 Seyfert AGN, assuming that 'single scattering' dominates. We get the result that the theoretical degree ofpolarization of Seyfert 2 should range from 10 to 80 percent. NGC 1068 fits well this simplemodel. For other AGNs with degrees of polarization below 10 percent, dust transition effectshould be considered. Under this model, we also get the angular distribution of the scatteredflux, dependent on both the half openning angle of torns() and the viewing angle .We find an interesting feature in the angular distribution: when , all the curvespass through the same point. This indicates that the ratio between the flux in the observeddirection and total scattered flux is a constant(~16%). This may be a good check of thetorns model.
基金
国家自然科学基金
国家攀登计划资助项目
关键词
赛弗特星系
分子环
偏振
汤姆逊散射机制
active galactic nuclei - Seyfert galaxy - torns - polarization