VLBI observations of bright AGN jets with KVN and VERA Array (KaVA): Evaluation of Imaging Capability

TL;DR

This paper presents initial high-resolution imaging results of bright AGN jets using the KaVA VLBI array, demonstrating its capability to resolve complex structures with high dynamic range, comparable to established arrays.

Contribution

First imaging observations of bright AGNs with KaVA, showing its high resolution and dynamic range, and validating its potential for AGN outflow studies.

Findings

KaVA achieved angular resolutions better than 1.4 mas at 23 GHz and 0.8 mas at 43 GHz.

KaVA attained a high dynamic range of ~1000, surpassing VERA.

Images reveal complex AGN jet structures consistent with previous VLBA observations.

Abstract

The Korean very-long-baseline interferometry (VLBI) network (KVN) and VLBI Exploration of Radio Astrometry (VERA) Array (KaVA) is the first international VLBI array dedicated to high-frequency (23 and 43 GHz bands) observations in East Asia. Here, we report the first imaging observations of three bright active galactic nuclei (AGNs) known for their complex morphologies: 4C 39.25, 3C 273, and M 87. This is one of the initial result of KaVA early science. Our KaVA images reveal extended outflows with complex substructure such as knots and limb brightening, in agreement with previous Very Long Baseline Array (VLBA) observations. Angular resolutions are better than 1.4 and 0.8 milliarcsecond at 23 GHz and 43 GHz, respectively. KaVA achieves a high dynamic range of ~1000, more than three times the value achieved by VERA. We conclude that KaVA is a powerful array with a great potential for the study of AGN outflows, at least comparable to the best existing radio interferometric arrays.