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arXiv 0910.2681astro-ph.CO
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活动星系核、类星体与星系环境的关系

The Relationship of Active Galactic Nuclei & Quasars With Their Local Galaxy Environment

Natalie Erin Strand

备注：
PhD dissertation, deposited 27 July 2009
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摘要：

我们探讨了当地的环境是如何与各种光度的活动星系核（AGN）的属性。最近的模拟和观测都集中在这样一个观点上，即类星体的极端亮度，活动星系核中最明亮的，是在富含气体的星系的主要合并中得到的。在这样的图片中，类星体，最高亮度的活动星系核，预计将位于小尺度上星系密度较高的区域，那里更有可能发生合并。然而，在这张图片中，在低光度活动星系核中观察到的活动是由于长期的过程，是不太依赖于本地星系密度。为了验证这一假设，我们比较了本地光度星系密度周围的光谱I型和II型类星体的本地密度低光度光谱I型和II型活动星系核周围的千秒差距尺度。为了最大限度地减少投影效应和光度星系样本的演变，我们用来表征活动星系核环境，我们把我们的随机控制样本在相同的红移作为我们的活动星系核和周围的活动星系核和控制目标施加一个狭窄的红移窗口。我们的结果支持这些合并模型明亮的活动星系核的起源。我们发现，最亮的源有overdensities增加的最小尺度相比，较暗的来源。此外，我们调查的类星体和活动星系核环境本身的性质，发现在明亮的I型源的环境中，早型星系的密度增加，表明它们位于比昏暗的源更丰富的星系团环境。我们测量增加类星体黑洞质量的增加，与著名的M_{DMH} - M_{BH}的关系，并找到证据淬火的环境中的高吸积效率I型类星体。

英文摘要：

We explore how the local environment is related to properties of active galactic nuclei (AGNs) of various luminosities. Recent simulations and observations are converging on the view that the extreme luminosity of quasars, the brightest of AGNs, is fueled in major mergers of gas-rich galaxies. In such a picture, quasars, the highest luminosity AGNs, are expected to be located in regions with a higher density of galaxies on small scales where mergers are more likely to take place. However, in this picture, the activity observed in low-luminosity AGNs is due to secular processes that are less dependent on the local galaxy density. To test this hypothesis, we compare the local photometric galaxy density on kiloparsec scales around spectroscopic type I and type II quasars to the local density around lower-luminosity spectroscopic type I and type II AGNs. To minimize projection effects and evolution in the photometric galaxy sample we use to characterize AGN environments, we place our random control sample at the same redshift as our AGNs and impose a narrow redshift window around both the AGNs and control targets. Our results support these merger models for bright AGN origins. We find that the brightest sources have overdensities that increase on the smallest scales compared to dimmer sources. In addition, we investigate the nature of the quasar and AGN environments themselves and find that the increased overdensity of early-type galaxies in the environments of bright type I sources suggests that they are located in richer cluster environments than dim sources. We measure increased environment overdensity with increased quasar black hole mass, consistent with the well-known M_{DMH}-M_{BH} relationship, and find evidence for quenching in the environments of high accretion efficiency type I quasars.

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