PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE 107, Page 43-50, https://doi.org/10.69646/14sbac06p
PPROCEEDINGS OF THE XIV SERBIAN-BULGARIAN ASTRONOMICAL CONFERENCE, Vrnjačka Banja, Serbia, September 23-27, 2024, Eds. Milan S. Dimitrijević, Evgeni Semkov, Zoran Simić, Goran Damljanović, Momchil Dechev
Published by: Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia

Compact radio sources, radio-emitting active galactic nuclei, are scarce objects, yet important as reference points for astrometric, astrophysical, and spacecraft navigation applications. We present over 3900 potential new compact radio sources derived from a cross- match between the Very Large Array Sky Survey (VLASS) radio catalogue and the recently published Quaia quasar catalogue. The VLASS catalogue provides a list of individual radio sources identified at 3 GHz with flux densities >~ 1 mJy, while the Quaia catalogue is derived from the Gaia optical astrometric catalogue by selecting sources with negligible proper motion and performing a k-means search method on colour–colour parameter spaces to extract quasars. We find more than 45 000 matched sources between the two catalogues with separations less than 2" from which more than 3900 present themselves as high-fidelity compact radio source candidates by having radio flux density > 20 mJy and a compactness ratio > 0.8. A proposal for observing 80 of these sources has been accepted by the European Very Long Baseline Interferometry Network which should validate the candidates and provide constraints on the parent sample. A follow-up analysis of the cosmologically important properties of the sources will be valuable, e.g. an analysis of the radio-loudness, its correlation to the spatial density in clusters and voids, and the correlation to colour–colour parameter spaces.