A Bar Fuels a Supermassive Black Hole?: Host Galaxies of Narrow-Line Seyfert 1 Galaxies
A Bar Fuels a Supermassive Black Hole?: Host Galaxies of Narrow-Line Seyfert 1 Galaxies
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DOI：
10.1086/510204
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发表时间：
2006-10
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影响因子：
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通讯作者：
K. Ohta;K. Aoki;T. Kawaguchi;Gaku Kiuchi
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文献类型：
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作者：
K. Ohta;K. Aoki;T. Kawaguchi;Gaku Kiuchi
我们给出了附近50个窄线塞弗特1星系（NLS 1）的光学图像，这些星系覆盖了2001年已知的所有z < 0.0666且δ ≥ -25°的NLS 1。在50个NLS 1中，40个图像是我们的观测新获得的，10个图像来自存档数据。基于NLS 1处于超大质量黑洞（BH）演化的早期阶段这一假设，我们对NLS 1宿主星系的形态进行了研究，通过观察活动星系核（AGN）的早期阶段来探讨其触发机制.利用这些图像，我们用目测和定量的方法进行了形态学分类，发现NLS 1在光学波段出现了较高的条频率;盘星系中棒频率为85% ± 7（64%-71%），比宽线Seyfert 1星系（BLS 1 s）和正常盘状星系的（40%-70%）要多，尽管其重要性微不足道。我们的结果证实了Crenshaw及其同事对19个NLS 1的类似分析。频率与H II/星暴星系相当。我们还检查了棒频率与宽Hβ发射线宽度、埃丁顿比和BH质量的关系，但没有观察到明显的趋势。可能的影响，如从NLS 1 s的进化序列BLS 1 s，进行了简要讨论。
We present optical images of nearby 50 narrow-line Seyfert 1 galaxies (NLS1s) that cover all the NLS1s at z < 0.0666 and δ ≥ -25° known in 2001. Among the 50 NLS1s, 40 images are newly obtained by our observations and 10 images are taken from archive data. Motivated by the hypothesis that NLS1s are in an early phase of a supermassive black hole (BH) evolution, we present a study of NLS1 host galaxy morphology to examine trigger mechanism(s) of active galactic nuclei (AGNs) by seeing the early phase of AGN. With these images, we made morphological classification by visual inspection and by quantitative method, and found a high bar frequency of the NLS1s in the optical band; the bar frequency is 85% ± 7% among disk galaxies (64%-71% in total sample) which is more frequent than that (40%-70%) of broad-line Seyfert 1 galaxies (BLS1s) and normal disk galaxies, although the significance is marginal. Our results confirm the claim by Crenshaw and coworkers with a similar analysis for 19 NLS1s. The frequency is comparable to that of H II/starburst galaxies. We also examined the bar frequency against width of the broad Hβ emission line, Eddington ratio, and BH mass, but no clear trend is seen. Possible implications, such as an evolutionary sequence from NLS1s to BLS1s, are discussed briefly.