X-ray study for the Unified Seyfert Model and evolution of AGN

我们进行这项研究的动机是为了检验统一塞弗特模型，并揭示塞弗特星系和星爆星系之间的进化联系。在统一Seyfert模型中，Seyfert 2星系与Seyfert 1星系具有相同的核，并且核被周围物质遮挡。日本的x射线卫星Ginga发现了几个Seyfert 2星系，它们的x射线光谱可以用该模式很好地解释。然而，目前尚不清楚该模型是否适用于所有塞弗特2星系。为了解决这一问题，我们制作了无x射线偏置的样品，然后用日本x射线卫星ASCA对其进行观测。我们在所有目标星系中都发现了被遮挡的原子核，它们的亮度与统一的塞弗特模型预测的塞弗1星系的亮度相似。我们研究了遮蔽物质的柱密度分布，发现Seyfert 2星系的柱密度相似，均为10^<23> cm^<-2>。2) Sanders提出了AGNAn活动星系核的演化情景。为了验证这一设想，我们观测到Seyfert 2星系的弱活动和复合类型的Seyfert和星暴活动与ASCA。我们发现它的光谱性质与星暴星系或LINER非常相似。最近的光学观测表明，除了NGC1667之外，这些星系应该被归类为LINER。我们的观测和光学鉴定表明以前的分类是不完整的。

Our motivations for this research are to examine the Unified Seyfert model and to reveal an evolutional link between Seyfert galaxies and Starburst galaxies.1)examination of the Unified SeyfertmodelIn the unified Seyfert model, Seyfert 2 galaxies have the same nuclei as those of Seyfert 1 galaxies, and the nuclei are obscured by surrounding matter. The Japanese X-ray sattelite Ginga found several Seyfert 2 galaxies which X-ray spectra could be well explained by the mode. However, it is still unclear whether the model can be applied for all Seyfert 2 galaxies. We made non X-ray bias sample in order to resolve this problem, then we observed them with the Japanese X-ray satellite ASCA.We found obscured nuclei from all of our targets, and their luminosities were similar to those of Seyfer 1 galaxies as predicted by the unified Seyfert model. We studied the disctribution of column density of the obscuring matter, then found that Seyfert 2 galaxies have similar clumn density of 10^<23> cm^<-2> each other.2)evolution of AGNAn evolutional scenario of active galactic nucleus were proposed by Sanders. In order to examine this scenario, we observed Seyfert 2 galaxied with weak activity and composite type of Seyfert and starburst activities with ASCA.We found that the spectral property was quite similar to that of starburst galaxy or LINER.Recent optical observations suggests that these galaxies except for NGC1667, should be classified into LINER.Our observations and the optical identification indicate that previous classification were not complete.