RADIAL VELOCITY OFFSETS DUE TO MASS OUTFLOWS AND EXTINCTION IN ACTIVE GALACTIC NUCLEI
RADIAL VELOCITY OFFSETS DUE TO MASS OUTFLOWS AND EXTINCTION IN ACTIVE GALACTIC NUCLEI
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DOI：
10.1088/0004-637x/708/1/419
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发表时间：
2009-11
期刊：
影响因子：
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通讯作者：
D. Crenshaw;H. R. Schmitt;S. Kraemer;R. Mushotzky;J. Dunn
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作者：
D. Crenshaw;H. R. Schmitt;S. Kraemer;R. Mushotzky;J. Dunn
我们研究了红移小于0.043的塞弗特星系中窄的发射线和主星系线之间的径向速度偏差(恒星吸收和H I 21厘米发射)。我们发现，样本中35%的Seyfert相对于其宿主星系S−1显示出蓝移超过50公里的[O III]发射线，而只有6%的Seyfert显示出如此大的红移，与大多数前人的研究定性一致。我们还发现，Seyfert 1星系比Seyfert 2星系有更大比例的蓝移。利用哈勃空间望远镜/空间望远镜成像光谱仪对Seyfert 2星系NGC1068和Seyfert 1星系NGC4151的空间分辨光谱，我们建立了它们的窄线区(NLR)和星系内盘的几何模型，并说明了这些模型如何解释这两个Seyfert星系的坍塌STIS光谱中蓝移的[O III]发射线。我们的结论是，NLR中电离气体的大量流出和内盘中尘埃的消光(主要以尘埃螺旋的形式)的结合是造成赛弗特星系速度偏差的主要原因。不需要更奇特的解释。我们讨论了这一结果对在高红移活动星系核中发现的速度偏移量的影响。
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−1, 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 Hubble Spce Talescope/Space Telescope Imaging Spectrograph 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 active galactic nuclei.