We present full polarization Very Long Baseline Array (VLBA) observations at 5 and 15 GHz of 24 compact active galactic nuclei (AGNs). 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°. 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 eight 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.
展开▼
机译：我们提出了在24个紧凑的有源银河核（AGNs）的5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，在该镜头中，它在15°以北的偏角处与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。在典型的动态范围为500：1的5 GHz下，所有24个源均被检测并成像，而在15 GHz下，24个源中有21个被检测并成像。在5 GHz和15 GHz的八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。
展开▼
