The most compact bright radio-loud AGN -- I. A new target sample selected for the space VLBI

TL;DR

This paper identifies 49 new bright, compact, radio-loud AGN suitable for space VLBI at mm wavelengths, expanding the catalog of potential targets for high-resolution radio astronomy and future space VLBI missions.

Contribution

It presents a new sample of 49 compact AGN selected from WMAP and Planck data, not previously observed with ground-based VLBI at 86 GHz, enhancing the list of candidates for space VLBI.

Findings

Identified 49 new bright, compact AGN for mm-VLBI.

Compared new sample with previous compact AGN samples.

Formed a catalog of over 160 AGN for future observations.

Abstract

We investigated the archival ground-based VLBI images of the extragalactic radio sources included in both the {\it Wilkinson Microwave Anisotropy Probe (WMAP)} and the {\it Planck} catalogues, and selected 49 bright and compact sources as potential targets for space Very Long Baseline Interferometry (VLBI) observations at mm wavelengths. These sources have a flat radio continuum spectrum between 33 and 94~GHz. They are identified as core-dominated active galactic nuclei (AGN), located at declinations above $-40\degr$, and have never been observed with ground-based VLBI at 86~GHz. The radio properties of the 49 new sources are presented. We compare this new sample with similar samples of compact AGN available from earlier studies. The new candidates, together with the existing bright compact AGN sample identified from 86-GHz ground-based VLBI imaging surveys, form a catalogue of more than 160 AGN. These could be primary targets for mm-VLBI observations on the ground, as well as for future mm-wavelength space VLBI missions such as the project with two satellites currently under study in China.