The CLASS BL Lac sample: The Radio Luminosity Function
The CLASS BL Lac sample: The Radio Luminosity Function
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DOI：
10.1093/mnras/stt065
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发表时间：
2013-01
影响因子：
4.8
通讯作者：
M. Marchã;A. Caccianiga
中科院分区：
文献类型：
--
作者：
M. Marchã;A. Caccianiga
本文介绍了一个新的样本BL Lac对象选择深（30兆焦耳）无线电调查的平谱射电源（类blazar调查，以下简称CBS）。该样品是最大的定义明确的样品在低功率制度，共有130个来源，其中55个满足“经典”的光学BL Lac选择标准，其余的具有难以区分的无线电特性。本研究的主要目标是建立在坚实的统计基础上的低射电光度的射电光度函数（RLF），以前的样品还没有能够调查。窥视较低功率的好处是有可能寻找LF的扁平化，这是由聚束模型预测的一个特征，但仍然难以观测证实。在这项研究中，我们第一次将BL Lac RLF扩展到非常低的无线电功率-10 22 W/Hz，即比文献中现有的RLF低两个数量级。在这个过程中，我们确认的重要性，采用一个更广泛的，更有物理意义的分类标准，以避免系统的低光度BL拉克的缺失。由于良好的统计数据，我们证实了BL Lac种群存在微弱但显著的正宇宙学演化，并且我们首次检测到L10 25 W/Hz处的RLF平坦化，这与光束模型的预测一致。
This paper presents a new sample of BL Lac objects selected from a deep (30 mJy) radio survey of flat spectrum radio sources (the CLASS blazar survey, henceforth CBS). The sample is one of the largest well defined samples in the low power regime with a total of 130 sources of which 55 satisfy the ’classical’ optical BL Lac selection criteria, and the rest have indistinguishable radio properties. The primary goal of this study is to establish the Radio Luminosity Function (RLF) on firm statistical ground at low radio luminosities where previous samples have not been able to investigate. The gain of taking a peek at lower powers is the possibility to search for the flattening of the LF which is a feature predicted by the beaming model but which has remained elusive to observational confirmation. In this study we extend for the first time the BL Lac RLF down to very low radio powers � 10 22 W/Hz, ie, two orders of magnitude below the RLF currently available in the literature. In the process we confirm the importance of adopting a broader, and more physically meaningful set of classification criteria to avoid the systematic missing of low luminosity BL Lacs. Thanks to the good statistics we confirm the existence of weak but significant positive cosmological evolution for the BL Lac population, and we detect, for the first time the flattening of the RLF at L � 10 25 W/Hz in agreement with the predictions of the beaming model.