Optical Polarisation Variability of Radio-Loud Narrow-Line Seyfert 1 Galaxies: Search for Long Rotations of the Polarisation Plane

Abstract: This work describes multi-site optical polarimetric observations of several radio-loud Narrow Line Seyfert 1 galaxies. This source class, and the sources in this study, were discovered to be detectable at gamma-ray energies by the Large Area Telescope (LAT) aboard the Fermi satellite. GSFC has played a key role in the development, launch, and operation of Fermi/LAT.