Vol. 576
In section 6. Interstellar and circumstellar matter

Pulsar polarisation below 200 MHz: Average profiles and propagation effects

by A. Noutsos, C. Sobey, V. I. Kondratiev, et al., A&A 576, A62

The authors present the highest quality low radio frequency polarization observations, obtained with LOFAR, of a substantial sample of classical and millisecond pulsars to study bifringence in the pulsar magnetosphere and the origin of the fine structure in the pulse profiles. An especially notable feature of this paper is the extreme care taken to correct for terrestrial ionospheric propagation effects (Sect. 3), and examine in detail the contribution of interstellar propagation. They also determine the heights for the low-frequency pulsing, deriving a frequency dependence for their best case and a general height of a few hundred kilometers for the site of origin. While their conclusion is that the sample does not provide strong support for pulsar magnetospheric bifringence, the details of the authors' approach are a model for any future studies of low-frequency emission from pulsars.