Multi-Faceted Emission Properties of PSR J2129+4119 Observed with FAST

TL;DR

This study of PSR J2129+4119 with FAST reveals complex emission behaviors, including nulling, drifting, and microstructures, demonstrating that pulsars can remain active near the death line contrary to previous assumptions.

Contribution

The paper provides the first detailed single-pulse analysis of PSR J2129+4119, showing sustained emission and complex modulation patterns despite its position below the traditional death line.

Findings

Nulling fraction is 8.13%, with short null durations.

Detection of phase-modulated subpulse drifting and beat-like modulation.

Presence of microstructures with a mean periodicity of 4.57 ms.

Abstract

We present a detailed single-pulse study of the long-period pulsar PSR J2129+4119 using high-sensitivity FAST observations. Despite locating well below the traditional death line, the pulsar exhibits sustained and multi-modal emission behavior, including nulls, weak pulses, regular emission, and occasional bright pulses. The nulling fraction is measured to be $8.13\% \pm 0.51\%$, with null durations typically under four pulse periods. Fluctuation spectral analysis reveals both phase-modulated subpulse drifting and intermittent beat-like modulation. At the same time, polarization profiles show high linear polarization and stable polarization position angle (PPA) swings consistent with a near-tangential sightline geometry. Quasi-periodic microstructures are detected in 11.54\% of regular pulses, with a mean periodicity and width of 4.57 ms and 4.30 ms, respectively. A well-defined scintillation arc in the secondary spectrum confirms the presence of a localized scattering screen. These results indicate that PSR J2129+4119 remains magnetospherically active and coherently emitting despite its low energy loss rate, offering key insights into pulsar emission physics near the death line.