Radio polarimetry of Galactic centre pulsars
  To study the strength and structure of the magnetic field in the Galactic
centre (GC) we measured Faraday rotation of the radio emission of pulsars which
are seen towards the GC. Three of these pulsars have the largest rotation
measures (RMs) observed in any Galactic object with the exception of Sgr A*.
Their large dispersion measures, RMs and the large RM variation between these
pulsars and other known objects in the GC implies that the pulsars lie in the
GC and are not merely seen in projection towards the GC. The large RMs of these
pulsars indicate large line-of-sight magnetic field components between ~ 16-33
microgauss; combined with recent model predictions for the strength of the
magnetic field in the GC this implies that the large-scale magnetic field has a
very small inclination angle with respect to the plane of the sky (~ 12
degrees). Foreground objects like the Radio Arc or possibly an ablated, ionized
halo around the molecular cloud G0.11-0.11 could contribute to the large RMs of
two of the pulsars. If these pulsars lie behind the Radio Arc or G0.11-0.11
then this proves that low-scattering corridors with lengths >~ 100 pc must
exist in the GC. This also suggests that future, sensitive observations will be
able to detect additional pulsars in the GC. Finally, we show that the GC
component in our most accurate electron density model oversimplifies structure
in the GC.
