【摘要】 借助HST高分辨率观测图像所分离的Seyfert星系核的光学光度,以及IUE观测的紫外流量,来推算Seyfert星系核的大蓝包特征谱指数(α)(Fν～ν-α)并进行统计。发现样本的平均谱指数是-0.55,比Sloan数字天空巡天(SDSS)类星体合成谱幂律拟合谱指数(0.46)要小,更接近于经典吸积盘理论所预测的光学—紫外谱指数(-0.3)。尽管谱指数分布仍然较宽,但与星系总辐射所推测的大蓝包谱指数αT相比,大多数天体都有所降低。另外发现,相比Ⅰ型来说,SeyfertⅡ型星系核大蓝包特征谱指数的降低有异常的大,可能与星系盘上紫外辐射在Ⅱ型总辐射中占有相当大的份额有关。更多还原

【Abstract】 <Abstrcat>Based on the nuclear magnitude in the optical,inferred from the decomposition of the high-resolution optical image of HST WFPC1/2,and the ultraviolet flux,observed by IUE,the power law spectral index（α）(Fν～ν^-α) of Big Blue Bump （BBB） emission is measured for the Seyfert galactic nuclei.The average value of them is -0.55,less than the value of composite spectral index （0.46） of SDSS,close to the expected value （-0.3） of the spectral index for classic accretion disk emission in the same spectral region.Compared to the α^T,the BBB spectral index,measured from the total emission of galaxy,the above index α has a lower value for most Seyfert objects in our sample,although still with a wider distribution.Additionally,we conjecture that some type Ⅱ Seyfert objects have abnormal decrease,compared to type Ⅰ,due to the ultraviolet emission of galactic disk without proper deduction from the total galactic emission.更多还原