We present full polarization Very Long Baseline Array (VLBA) observations at 5 GHz and 15 GHz of 24 compact active galactic nuclei (AGN). These sources were observed as part of a pilot project to demonstrate the feasibility of conducting a large VLBI survey to further our understanding of the physical properties and temporal evolution of AGN jets. The sample is drawn from the Cosmic Lens All-Sky Survey (CLASS) where it overlaps with the Sloan Digital Sky Survey at declinations north of 15 degrees. There are 2100 CLASS sources brighter than 50 mJy at 8.4 GHz, of which we have chosen 24 for this pilot study. All 24 sources were detected and imaged at 5 GHz with a typical dynamic range of 500:1, and 21 of 24 sources were detected and imaged at 15 GHz. Linear polarization was detected in 8 sources at both 5 and 15 GHz, allowing for the creation of Faraday rotation measure (RM) images. The core RMs for the sample were found to have an average absolute value of 390 +/- 100 rad/m^2. We also present the discovery of a new Compact Symmetric Object, J08553+5751. All data were processed automatically using pipelines created or adapted for the survey.
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机译：我们提出了在24个紧凑的活动银河核（AGN）的5 GHz和15 GHz处的全极化甚长基线阵列（VLBA）观测结果。观察到这些来源是一个试点项目的一部分，以演示进行大型VLBI调查以进一步了解AGN射流的物理特性和时间演变的可行性。该样本是从“宇宙镜头全天候测量”（CLASS）中提取的，它在15度以北偏角处与Sloan Digital Sky Survey重叠。在8.4 GHz频率下，有2100个CLASS光源的亮度超过50 mJy，其中我们为该试验研究选择了24个。在500 GHz的典型动态范围内，在5 GHz下检测和成像所有24个源，在15 GHz下检测和成像24个源中的21个。在5 GHz和15 GHz的8个光源中检测到线性极化，从而可以创建法拉第旋转测量（RM）图像。发现样品的核心RM具有390 +/- 100 rad / m ^ 2的平均绝对值。我们还介绍了新的紧凑对称对象J08553 + 5751的发现。使用为调查创建或修改的管道自动处理所有数据。
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