Demonstration of Ultrawideband Polarimetry Using VLBI Exploration of Radio Astrometry (VERA)

TL;DR

This paper details recent technical advancements in VERA's radio telescopes, including ultrawideband and dual-polarization systems, enhancing sensitivity and enabling detailed magnetic field studies in astrophysical phenomena.

Contribution

Introduction of ultrawideband and dual-polarization systems on VERA telescopes, improving VLBI sensitivity and polarimetric capabilities for astrophysical research.

Findings

Polarization maps of extragalactic sources at 22 and 43 GHz

Enhanced sensitivity from wider bandwidths

Successful demonstration of VLBI polarimetry with VERA

Abstract

We report on recent technical developments in the front- and back-ends for the four 20 m radio telescopes of the Japanese Very-Long-Baseline Interferometry (VLBI) project, VLBI Exploration of Radio Astrometry (VERA). We present a brief overview of a dual-circular polarization receiving and ultrawideband (16 Giga bit s$^{-1}$) recording systems that were installed on each of the four telescopes operating at 22 and 43 GHz bands. The wider-band capability improves the sensitivity of VLBI observations for continuum emission, and the dual-polarization capability enables the study of magnetic fields in relativistic jets ejected from supermassive black holes in active galactic nuclei and in sites of star formation and around evolved stars. We present the linear polarization intensity maps of extragalactic sources at 22 and 43 GHz obtained from the most recent test observations to show the state of the art of the VERA polarimetric observations. At the end of this article, given the realization of VLBI polarimetry with VERA, we describe the future prospects for scientific aims and further technical developments.