Radio Pulsar B0950$+$08: Radiation in Magnetosphere and Sparks above Surface

Abstract

We observed the nearby 100$\%$-duty-cycle radio pulsar B0950+08 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We obtained the polarization profile for its entire rotation, which enabled us to investigate its magnetospheric radiation geometry and the polar cap sparking pattern. After we excluded part of the profile in which the linear polarization factor is low ($\lesssim 30\%$) and potentially contaminated by position angle jumps, the rest of the polarization position angle swing fits a classical rotating vector model (RVM) well. The bestfit RVM indicates that the inclination angle, $\alpha$, and the impact angle, $\beta$, of this pulsar, are 100.5${}^{\circ }$ and $-$33.2${}^{\circ }$, respectively, suggesting that the radio emission comes from two poles.We find that, in such RVM geometry, either the annular vacuum gap or the core vacuum gap model would require that the radio emissions come from a high-altitude magnetosphere with heights from $\sim 0.25R_{\mathrm{LC}}$ to $\sim 0.56R_{\mathrm{LC}}$, with $R_{\mathrm{LC}}$ being the light cylinder radius. Both the main and inter-pulses' sparking points are located away from the magnetic pole, which could be relevant to the physical conditions on the pulsar surface.

16 pages,9 figures. Accepted for publication in ApJ

References in corpus (8)

• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• The Fundamental Performance of FAST with 19-beam Receiver at L Band
• A Fan Beam Model for Radio Pulsars. I. Observational Evidence
• The Thousand-Pulsar-Array programme on MeerKAT XI: Application of the rotating vector model
• Dual-frequency single-pulse study of PSR B0950+08
• The radio signal of PSR B0950+08 is detected over the whole pulse phase
• Neutron Star versus Neutral Star: On the 90th anniversary of Landau's publication in astrophysics
• Polarization Measurements of Arecibo-Sky Pulsars: Faraday Rotations and Emission-Beam Analyses

Cited by in corpus (1)

• PSR B0943+10: Mode Switch, Polar Cap Geometry, and Orthogonally Polarized Radiation