POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths - II. Widespread circular polarization

We are grateful to Daniel Homan (Denison University, USA) for valuable comments and for sharing unpublished data, and to Ioannis Myserlis (MPIfR, Germany) for a careful reading of the manuscript. We thank an anonymous referee for insightful and helpful comments. This paper is based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). CT thanks the GILDAS software group, notably Sebastien Bardeau, for competent and rapid support. IA acknowledges support by a Ramon y Cajal grant of the Ministerio de Economia y Competitividad (MINECO) of Spain. The research at the IAA-CSIC was supported in part by the MINECO through grants AYA2016-80889-P, AYA2013-40825-P and AYA2010-14844, and by the regional government of Andalucia through grant P09-FQM-4784. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We have also made use of NASA's Astrophysics Data System Bibliographic Services.