Measuring pulsar rotation measures

Pulsar rotation measures (RMs) are measured by fitting the position angle of the linear polarization over a range of observing frequencies as:

${\displaystyle \psi ={\rm {RM}}\lambda ^{2}}$

where ${\displaystyle \lambda =c/f}$ where ${\displaystyle f}$ is the observing frequency.

Measured pulsar RMs vary, in part, because of the Earth's ionosphere. This ionospheric correction can be estimated using the International Reference Ionosphere (IRI) model.

Using pulsar rotation measures