VLBA Imaging Polarimetry of Active Galactic Nuclei: An Automated Approach

We present full polarization Very Long Baseline Array (VLBA) observations at5 GHz and 15 GHz of 24 compact active galactic nuclei (AGN). These sources wereobserved as part of a pilot project to demonstrate the feasibility ofconducting a large VLBI survey to further our understanding of the physicalproperties and temporal evolution of AGN jets. The sample is drawn from theCosmic Lens All-Sky Survey (CLASS) where it overlaps with the Sloan Digital SkySurvey at declinations north of 15 degrees. There are 2100 CLASS sourcesbrighter than 50 mJy at 8.4 GHz, of which we have chosen 24 for this pilotstudy. All 24 sources were detected and imaged at 5 GHz with a typical dynamicrange of 500:1, and 21 of 24 sources were detected and imaged at 15 GHz. Linearpolarization was detected in 8 sources at both 5 and 15 GHz, allowing for thecreation of Faraday rotation measure (RM) images. The core RMs for the samplewere found to have an average absolute value of 390 +/- 100 rad/m^2. We alsopresent the discovery of a new Compact Symmetric Object, J08553+5751. All datawere processed automatically using pipelines created or adapted for the survey.