A Wide and Deep Exploration of Radio-detected Active Galactic Nuclei with Subaru HSC (WERGS). XIII. High-z Radio Quasar Selection from HSC--VLASS over about1200 deg squared
Researchers used Subaru HSC and VLASS data to identify approximately 400 high-redshift radio AGN candidates across 1,200 square degrees. By employing a color-based dropout technique rather than relying on ultra-steep radio spectra, they uncovered a more diverse population of early black holes, correcting previous biases in cosmic censuses.