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arXiv 1104.3550astro-ph.COastro-ph.HE
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活动星系核的晕占据分布

The Halo Occupation Distribution of Active Galactic Nuclei

Suchetana Chatterjee, Colin DeGraf, Jonathan Richardson, Zheng Zheng, Daisuke Nagai, Tiziana Di Matteo

摘要:

使用一个完全宇宙学的流体动力学模拟,自洽地结合了超大质量黑洞的生长和反馈以及星系形成的物理学,我们研究了环境因素的影响(例如,局域气体密度、黑洞反馈)对低光度活动星系核晕占据分布的影响。我们将平均占有函数分解为中心和卫星贡献,并计算条件光度函数(CLF)。活动星系核中心的CLF服从对数正态分布,随着红移的增加,CLF的平均值增加,散射度减小。我们分析了单个活动星系核的光变曲线,发现活动星系核的峰值光度与晕质量的相关性比瞬时光度更紧密。我们还计算了卫星活动星系核在中心活动星系核光度一定时的CLF。我们没有看到任何显着的相关性之间的卫星的数量与光度的中央活动星系核在一个固定的晕质量。我们还表明,对于光度大于10^42尔格/s的活动星系核样本,其平均占据函数对于活动星系核中心来说可以模拟为软化的阶跃函数,对于卫星群来说可以模拟为幂律。活动星系核在晕内的径向分布在所有红移处都遵循幂律,平均指数为-2.33 +/- 0.08。阐明了超大质量黑洞吸积和反馈的环境依赖性,为解释活动星系核成团的当前和未来测量提供了理论工具。

英文摘要:

Using a fully cosmological hydrodynamic simulation that self-consistently incorporates the growth and feedback of supermassive black holes and the physics of galaxy formation, we examine the effects of environmental factors (e.g., local gas density, black hole feedback) on the halo occupation distribution of low luminosity active galactic nuclei (AGN). We decompose the mean occupation function into central and satellite contribution and compute the conditional luminosity functions (CLF). The CLF of the central AGN follows a log-normal distribution with the mean increasing and scatter decreasing with increasing redshifts. We analyze the light curves of individual AGN and show that the peak luminosity of the AGN has a tighter correlation with halo mass compared to instantaneous luminosity. We also compute the CLF of satellite AGN at a given central AGN luminosity. We do not see any significant correlation between the number of satellites with the luminosity of the central AGN at a fixed halo mass. We also show that for a sample of AGN with luminosity above 10^42 ergs/s the mean occupation function can be modeled as a softened step function for central AGN and a power law for the satellite population. The radial distribution of AGN inside halos follows a power law at all redshifts with a mean index of -2.33 +/- 0.08. Incorporating the environmental dependence of supermassive black hole accretion and feedback, our formalism provides a theoretical tool for interpreting current and future measurements of AGN clustering.

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