Relations between Galaxy Formation and the Environments of Quasars
Relations between Galaxy Formation and the Environments of Quasars
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星系形成与类星体环境之间的关系
DOI：
10.1093/pasj/55.1.133
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发表时间：
2002
影响因子：
2.3
通讯作者：
Naoj
中科院分区：
文献类型：
--
作者：
M. Enoki;M. Nagashima;U. NaoteruGoudaOsako;Naoj
我们调查的环境，如星系的数量分布，使用半解析模型，其中包括星系和类星体的形成的基础上的层次聚类方案。我们假设一个超大质量黑洞是由冷气体的吸积提供燃料的，并且在类星体宿主星系与另一个星系的主要合并过程中，它是类星体活动的来源。这个主要的合并导致了宿主星系的球状体的形成。我们的模型不仅能再现局域宇宙中星系光度函数的一般形式，而且能再现观测到的超大质量黑洞质量与椭球体光度的关系、当前黑洞的质量函数和不同红移下的类星体光度函数。利用这个模型，我们预测了类星体晕的平均类星体数、类星体的偏置参数以及类星体周围星系数的概率分布。在我们的模型中，对每个晕中类星体平均数目的分析表明，星系的空间分布不同于类星体。此外，我们还计算了星系数的概率分布，发现在0.2 < z < 0.5时，大多数类星体可能位于星系群中。另一方面，在1 < z < 2时，大多数类星体似乎比在较低的红移时居住在更多样化的环境中;类星体居住在从小星系群到星系团的环境中。将这些预测与未来的观测结果进行比较，将使我们能够限制我们的类星体形成模型。
We investigate the environments of quasars such as number distribution of galaxies using a semi-analytic model which includes both galaxy and quasar formations based on the hierarchical clustering scenario. We assume that a supermassive black hole is fueled by accretion of cold gas and that it is a source of quasar activity during a major merger of the quasar host galaxy with another galaxy. This major merger causes spheroid formation of the host galaxy. Our model can reproduce not only general form of the galaxy luminosity functions in the local Universe but also the observed relation between a supermassive black hole mass and a spheroid luminosity, the present black hole mass function and the quasar luminosity functions at different redshifts. Using this model, we predict the mean number of quasars per halo, bias parameter of quasars and the probability distribution of the number of galaxies around quasars. In our model, analysis of the mean number of quasars per halo shows that the spatial distribution of galaxies is different from that of quasars. Furthermore, we found from calculation of the probability distribution of galaxy numbers that at 0.2 < z < 0.5, most quasars are likely to reside in galaxy groups. On the other hand, at 1 < z < 2 most quasars seem to reside in more varied environments than at a lower redshift; quasars reside in environments ranging from small groups of galaxies to clusters of galaxies. Comparing these predictions with observations in future will enable us to constrain our quasar formation model.