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arXiv 0911.0675astro-ph.CO
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活动星系核中物质外流和消光引起的径向速度偏移

Radial Velocity Offsets Due to Mass Outflows and Extinction in Active Galactic Nuclei

D. M. Crenshaw, H. R. Schmitt, S. B. Kraemer, R. F. Mushotzky, J. P. Dunn

摘要:

我们提出了一个研究的径向速度之间的偏移窄发射线和宿主星系线(恒星吸收和H I 21厘米发射)在Seyfert星系观测到的红移小于0.043。我们发现,35%的样品中的塞弗特显示[O III]发射线与蓝移相对于其宿主星系超过50公里/秒,而只有6%的红移这么大,在定性协议与大多数以前的研究。我们还发现,一个更大的百分比的塞弗特1星系比塞弗特2星系显示蓝移。使用HST/STIS空间分辨光谱的Seyfert 2星系NGC 1068和Seyfert 1星系NGC 4151,我们生成的几何模型的窄线区(NLR)和内星系盘,并显示这些模型可以解释蓝移的[O III]发射线在崩溃的STIS光谱这两个Seyfert。我们的结论是,在NLR和灭绝的尘埃内盘(主要是在尘埃螺旋的形式)的电离气体的质量外流的组合是主要负责的速度偏移在塞弗特星系。不需要更多的奇异解释。我们讨论了这一结果的影响,发现在高红移活动星系核的速度偏移。

英文摘要:

We present a study of the radial velocity offsets between narrow emission lines and host galaxy lines (stellar absorption and H I 21-cm emission) in Seyfert galaxies with observed redshifts less than 0.043. We find that 35% of the Seyferts in the sample show [O III] emission lines with blueshifts with respect to their host galaxies exceeding 50 km/s, whereas only 6% show redshifts this large, in qualitative agreement with most previous studies. We also find that a greater percentage of Seyfert 1 galaxies show blueshifts than Seyfert 2 galaxies. Using HST/STIS spatially-resolved spectra of the Seyfert 2 galaxy NGC 1068 and the Seyfert 1 galaxy NGC 4151, we generate geometric models of their narrow-line regions (NLRs) and inner galactic disks, and show how these models can explain the blueshifted [O III] emission lines in collapsed STIS spectra of these two Seyferts. We conclude that the combination of mass outflow of ionized gas in the NLR and extinction by dust in the inner disk (primarily in the form of dust spirals) is primarily responsible for the velocity offsets in Seyfert galaxies. More exotic explanations are not needed. We discuss the implications of this result for the velocity offsets found in higher redshift AGN.

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