Quasar luminosity functions are a fundamental probe of the growth and evolution of supermassive black holes. Measuring the intrinsic luminosity function is difficult in practice, due to a multitude of observational and systematic effects. As sample sizes increase and measurement errors drop, characterizing the systematic effects is becoming more important. It is well known that the continuum emission from the accretion disk of quasars is anisotropic --- in part due to its disk-like structure --- but current luminosity function calculations effectively assume isotropy over the range of unobscured lines of sight. Here, we provide the first steps in characterizing the effect of random quasar orientations and simple models of anisotropy on observed luminosity functions. We find that the effect of orientation is not insignificant and exceeds other potential corrections such as those from gravitational lensing of foreground structures. We argue that current observational constraints may overestimate the intrinsic luminosity function by as much as a factor of ~2 on the bright end. This has implications for models of quasars and their role in the Universe, such as quasars' contribution to cosmological backgrounds.
本文探讨了几个简单的模型变化之间的联系类星体,星系,和暗物质晕的红移1 < z < 6。这些模型的一个关键组成部分是,我们强制执行一个自洽的黑洞(BH)的历史跟踪BH质量和BH增长率在所有的红移。我们用一个简单的常数密度程序连接红移的物体,并选择一个基准模型,BH和星系增长率之间的关系是线性的,并以一种简单的方式与红移的演变。在这个基准模型中,我们发现类星体的光度函数(QLF)计算的“内在”的光度的基础上的BH质量或BH的增长率,然后选择一个模型的类星体的变化与对数正态分布或截断幂律分布的瞬时光度。这给出了四个模型的变化,我们拟合到观测到的QLF在每个红移。有了最佳拟合模型,我们对四种基准模型进行了详细的比较,并探索了BH-星系关系的基准模型的变化。每个模型变化都可以成功地拟合观察到的QLF,其形状通常由暗端的“固有”亮度和亮端变化引起的散射决定。我们专注于解释物理上不同的模型可以做出类似预测的原因,并确定哪些观测数据或物理参数在打破模型之间的简并性方面是最重要的。
On the relative CNO underabundance in quasar absorption systems at $z \sim 3$ arising from Population III enrichment and attenuation by intermediate-mass black holes and primordial baryon accretion
National Institute for Space Research (INPE), Instituto Nacional de Pesquisas Espaciais(国家空间研究所)
Measurements of quasar proximity zones with the Ly$α$ forest of DESI Y1 quasars
The Ohio State University(俄亥俄州立大学);Academia Sinica(中央研究院);The University of Utah(犹他大学);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);Boston University(波士顿大学)
Broad Band X-ray Constraints on the Accreting Black Hole in Quasar 4C 74.26
类星体4C 74.26的X射线数据先前已经用宽的Fe K $α$发射线和反射连续体建模,这些发射线和反射连续体起源于中心超大质量黑洞(SMBH)周围的吸积盘的内部,即强重力区。我们模拟宽带X射线光谱从$Suzaku$和$NuSTAR$与MYTORUS,自洽占铁K $α$线发射,以及直接和反射连续发射,从有限的柱密度的问题。一个狭窄的铁K $α$发射线起源于一个X射线再处理器与太阳能铁丰度远离中央SMBH是足以产生良好的适合所有的光谱。这是第一次,我们能够测量的全球范围内,视线外的列密度$\sim$ $1.5$到$\sim$ $2.9\times10^{24}$ cm $^{-2}$,即在康普顿厚制度,而视线列密度是康普顿薄在所有的观察。Fe K $α$发射谱线除一个观测值外,其余都未分辨。来自遥远物质的康普顿散射连续谱消除了对铁K $α$发射线的相对论加宽的需要,这是SMBH自旋测量所需的。解决线观测可以替代建模与相对论模型,但我们没有找到证据截断吸积盘模型。我们的结论是,这些4C 74.26数据中的X射线发射是不可能起源于内吸积盘区域,因此不能用于测量SMBH自旋。