中文摘要：

最近XMM—Newton观测NTSeyfert 1星系，NGC3783，除存在着6．4keV的铁Kα发射线外，还存在着很强的7．0keV的铁Kβ发射线，且两者之间的等值宽度（EW）之比难以由传统的“光电吸收-莹光机制”来解释．利用尤峻汉等人提出的Cerenkov线状发射机制可合理解释EWKα／EWKβ．给出了详细的模型考虑和理论计算，结果表明活动星系核中产生铁K线的机制不只有莹光机制还有Cerenkov线状辐射机制．两者共存于活动星系核（AGNs）中，而且以Cerenkov辐射机制为主．

英文摘要：

The update observation of XMM-Newton shows that, except for the iron Ka line at ,- 6.4 keV, there is also an apparent iron Kβ line at - 7.0 keV in Seyfert 1 galaxy NGC 3783 with intensity markedly higher than that predicted by the traditional fluoresence emission. The observed ratio of the equivalent widths EWKα/EWKβ≈ 3.43 is difficult to understand from the ‘photoelectric absorption-fluorescence emission＇ mechanism. In this paper, we argue that the new Cerenkov line-like radiation mechanism suggested by You et al. can provide a solution for the puzzle of EWKα/EWKβ. We present a detailed model consideration and theoretical calculation. Our calculated result shows that, except for the fluorescence emission, there coexists a Cerenkov line-like radiation mechanism in AGNs, which gives a significant contribution to the iron K-line emission, even moderately higher than the former.