Cause of frequency-dependent linear polarisation evolution in PSR J2051-0827

Determine the cause of the observed frequency-dependent evolution of Stokes Q and U in PSR J2051-0827, including the emergence of a stronger leading component at lower frequencies that produces changes in the linear polarisation profile.

Background

PSR J2051-0827 is a black widow binary exhibiting eclipses and strong orbital-phase-dependent propagation effects. During L-band observations, the Stokes Q and U profiles show multi-component structure and evolve with frequency, with a stronger leading component apparent at lower frequencies.

While such behavior could be related to complex propagation effects in the intra-binary medium, the specific mechanism is not identified in this work.

References

While the cause of this is not fully known, it is important to note that the linear polarisation profiles have been seen to vary as a function of both frequency and time in a magnetar \citep{Lower_etal2024} providing a unique probe of the relativistic, magnetized plasma within the near-field environment of these ultra-magnetic neutron stars.

— Magneto-Active Environments in Pulsar Binaries with the MeerKAT Telescope: I. Pulsar sample and their basic properties  (2604.02310 - Singha et al., 2 Apr 2026) in Section 3.2 (PSR J2051-0827)