The radiative subpulse modulation and spectral features of PSR B1929$+$10 with the whole pulse phase emission

TL;DR

This study uses FAST to reveal that PSR B1929+10 emits across the entire 360° of longitude, identifies new weak emission components, and analyzes its magnetosphere, revealing high-altitude emission regions and multiple modulation modes.

Contribution

First detection of extremely weak emission components and full 360° emission coverage in PSR B1929+10, with detailed polarization and magnetospheric analysis.

Findings

PSR B1929+10 exhibits complete 360° emission coverage.

Identified at least 15 pulse components and 5 modulation modes.

Detected narrowband features and polarization jumps in single pulses.

Abstract

In this work, we observe the nearby pulsar, PSR B1929$+$10, using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We find, for the first time, two new emission components with an extremely weak observed flux density of about $10^{-4}$ of the magnitude of the peak radio emission of PSR B1929$+$10. Our results show that the intrinsic radio emission of PSR B1929$+$10 covers the $360^{\circ}$ of longitude, demonstrating that this pulsar is a whole $360^{\circ}$ of longitude emission pulsar. We find at least 15 components of pulse emission in the average pulse profile. Additionally, we identify 5 modes of subpulse modulation in different emission regions, which differ from the pulse components. Moreover, the narrowband emission feature and the frequent jumps in the observed linear polarization position angle (PPA) are also detected in the single pulse of this pulsar. To understand the magnetosphere of this pulsar, we analyze the observed PPA variations across the whole $360^{\circ}$ of longitude and fit them using the classical rotating vector model (RVM). For the best-fit model, the inclination angle,$\alpha$, and the impact angle, $\beta$, of this pulsar are $55^{\circ}.56$ and $53^{\circ}.47$, respectively. Using the rotating magnetosphere approximation of the magnetic dipole field, we investigate the three-dimensional pulsar magnetosphere and the sparking pattern on the polar cap surface. Our analysis indicates that the extremely narrow zone of the polar cap, which is associated with a high-altitude magnetospheric region, is responsible for the weak emission window. This pulsar has extremely high-altitude magnetospheric radio emissions.