Different polarized components of the quasar 3C 286 revealed by FAST

TL;DR

This study uses FAST telescope data to analyze interplanetary scintillation effects on the polarized radio emissions of quasar 3C 286, revealing different emission regions and solar wind speeds.

Contribution

First detection of IPS effects on polarized flux densities of 3C 286 with high-time-resolution data from FAST, indicating multiple emission regions.

Findings

IPS affects Stokes I, Q, U but not V

Different polarization components originate from distinct regions

Estimated solar wind speed of approximately 637 km/s

Abstract

3C 286, a well-known radio calibrator, exhibits the stability in both of total flux density (FD) and polarization parameters. However, its stable and luminous interstellar radio signal may encounter interplanetary scintillation (IPS) due to density irregularities in the solar wind within the heliosphere. In this work, we analyze high-time-resolution observations of 3C 286 obtained with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) from 2019 to 2023. Our analysis reveals that IPS affects the polarized flux densities of the Stokes I, Q, and U parameters, whereas Stokes V shows no detectable IPS-induced variations. The IPS variations detected in Stokes I are synchronous with those in Stokes U, while those in Stokes Q exhibit greater randomness. The crosscorrelation function (CCF) results indicate no time delay between Stokes I and U, but a delay of approximately 2.8 seconds between Stokes I and Q. This suggests that the different polarized radio emissions of 3C 286 originate from distinct emission regions, specifically the core and the southwestern jet. Furthermore, the projections of the radio core and jet component onto the scintillation screen at 1 AU yield a solar wind plasma speed of $\sim 637$ km/s.