Studying Magnetic Fields using Low-frequency Pulsar Observations

TL;DR

This paper discusses how low-frequency pulsar observations with advanced radio telescopes can probe magnetic fields across various astrophysical environments, revealing insights into pulsar magnetospheres and the Galactic magnetic field structure.

Contribution

It presents recent results and ongoing research using LOFAR and MWA to study magnetic fields via pulsar observations, highlighting advancements and future prospects with the SKA.

Findings

Pulsar observations reveal magnetic field structures in the ISM and ionosphere.

Dispersion and Faraday rotation measurements map Galactic magnetic fields.

Low-frequency telescopes enhance understanding of pulsar magnetospheres.

Abstract

Low-frequency polarisation observations of pulsars, facilitated by next-generation radio telescopes, provide powerful probes of astrophysical plasmas that span many orders of magnitude in magnetic field strength and scale: from pulsar magnetospheres to intervening magneto-ionic plasmas including the ISM and the ionosphere. Pulsar magnetospheres with teragauss field strengths can be explored through their numerous emission phenomena across multiple frequencies, the mechanism behind which remains elusive. Precise dispersion and Faraday rotation measurements towards a large number of pulsars probe the three-dimensional large-scale (and eventually small-scale) structure of the Galactic magnetic field, which plays a role in many astrophysical processes, but is not yet well understood, especially towards the Galactic halo. We describe some results and ongoing work from the Low Frequency Array (LOFAR) and the Murchison Widefield Array (MWA) radio telescopes in these areas. These and other pathfinder and precursor telescopes have reinvigorated low-frequency science and build towards the Square Kilometre Array (SKA), which will make significant advancements in studies of astrophysical magnetic fields in the next 50 years.