A Mixture Evolution Scenario of the AGN Radio Luminosity Function. II. Do Low- and High-power Radio-loud AGNs Evolve Differently?
A Mixture Evolution Scenario of the AGN Radio Luminosity Function. II. Do Low- and High-power Radio-loud AGNs Evolve Differently?
复制标题
AGN 射电亮度函数的混合演化场景。
DOI：
10.3847/1538-4357/aa8463
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发表时间：
2017
影响因子：
4.9
通讯作者：
Mao Jirong
中科院分区：
文献类型：
--
作者：
Yuan Zunli;Wang Jiancheng;Zhou Ming;Qin Longhua;Mao Jirong
在前人工作的基础上，我们进一步证实了陡谱射电噪活动星系核的宇宙演化可以通过密度演化（DE）和光度演化（LE）的简单组合来再现。这种混合演化理论可以很好地解释射电活动星系核的光度演化。我们的模型成功地拟合了大量的数据的射电光度函数的陡谱源和多频源计数。模拟表明，DE缓慢增加，然后迅速减少，而LE迅速增加，直到更高的红移（至少）。我们发现一个高红移下降（即，红移截止）的陡谱射电源的数量密度，但我们不能断定这种下降是急剧或浅。我们认为，红移截止的发生与否主要取决于DE，而它的陡度是由LE决定的，但由于缺乏高红移的样本，不能很好地约束。最有趣的是，根据我们的混合演化方案，似乎没有必要为低功率和高功率无线电响亮的活动星系核不同的演变。这两种类型的源经历DE和LE的相同组合演化。
Following previous work, we further confirm that the cosmic evolution of steep-spectrum radio-loud AGNs (active galactic nuclei) can be reproduced by a simple combination of density evolution (DE) and luminosity evolution (LE). This mixture evolution scenario can naturally explain the luminosity-dependent evolution of radio-loud AGNs. Our models successfully fitted a large amount of data on radio luminosity functions of steep-spectrum sources and multi-frequency source counts. The modeling indicates that the DE slowly increases as out to , and then rapidly decreases as , while the LE rapidly increases as out to a higher redshift (at least ). We find a high-redshift decline (i.e., redshift cutoff) in the number density of steep-spectrum radio sources, but we cannot conclude whether such a decline is sharp or shallow. We believe that whether a redshift cutoff occurs or not depends mainly on DE, while its steepness is decided by LE, which, however, cannot be well constrained due to the lack of high-redshift samples. Most intriguingly, according to our mixture evolution scenario, there appears to be no need for different evolution for the low- and high-power radio-loud AGNs. Both types of sources experience the same combined evolution of DE and LE.