论文标题
在AGN光度函数的微弱末端建模明亮的Z = 6星系
Modelling a bright z = 6 galaxy at the faint end of the AGN luminosity function
论文作者
论文摘要
最近的深度调查揭示了高红移宇宙中微弱的活跃银河核（AGN）的种群，导致了有关其性质及其在电离时期的作用的各种讨论。我们使用Z = 6（$ M_ \ Star \ gtrsim 10^{10} M_ \ ODOT $）的明亮星系的宇宙学辐射流动力学模拟，该模拟载有一个积极生长的超级质量黑洞，以研究这些物体的性质。特别是，我们研究黑洞和星系如何共同发展，以及AGN和恒星种群对系统亮度预算的相对贡献。我们发现来自AGN的反馈对星系的性质没有强大的影响，也不会增加宿主的总电离光度。我们银河系的平均逃逸分数约为$ f _ {\ rm esc} \ sim 5 \％$。虽然我们的星系将在深X射线调查中被选为AGN，但大多数紫外线亮度源自恒星种群。这证实了星系人口从星系形成星系到类星体宿主的过渡，其明亮的Lyman -break星系（LBG），$ M _ {\ rm UV} $在重叠区域落在-22左右。我们的结果还表明，微弱的AGN并没有为恢复宇宙的贡献做出重大贡献。
Recent deep surveys have unravelled a population of faint active galactic nuclei (AGN) in the high redshift Universe, leading to various discussions on their nature and their role during the Epoch of Reionization. We use cosmological radiation-hydrodynamics simulations of a bright galaxy at z = 6 ($M_\star \gtrsim 10^{10} M_\odot$) hosting an actively growing super-massive black hole to study the properties of these objects. In particular, we study how the black hole and the galaxy co-evolve and what is the relative contribution of the AGN and of the stellar populations to the luminosity budget of the system. We find that the feedback from the AGN has no strong effect on the properties of the galaxy, and does not increase the total ionizing luminosity of the host. The average escape fraction of our galaxy is around $f_{\rm esc} \sim 5\%$. While our galaxy would be selected as an AGN in deep X-ray surveys, most of the UV luminosity is originating from stellar populations. This confirms that there is a transition in the galaxy population from star forming galaxies to quasar hosts, with bright Lyman-Break Galaxies (LBGs) with $M_{\rm UV}$ around -22 falling in the overlap region. Our results also suggest that faint AGN do not contribute significantly to reionizing the Universe.
