J-HERTz: a radio counterpart catalogue for J-PLUS

We present J-HERTZ (J-Plus Heritage Exploration of Radio Targets at Z <5) a new value-added catalogue associated with the J-PLUS DR3 release,including sources with counterparts at low radio frequencies detectedby the LOFAR LoTSS DR2 survey. The catalogue comprises about 470kobjects within a common area of approximately 2100 deg². J-HERTZ includes a machine-learning classification of the galaxies,QSOs and stars in the survey, based on Bayesian neural networks (BANNJOS, del Pino et al. 2024, submitted). Additionally, BANNJOS provides newphotometric redshifts for sources without previous spectroscopicobservations. The complete catalogue includes 370k galaxies,30k QSOs and 20k stars detected with high confidence (r < 20mag). In this work we describe the main properties of these threepopulations, including the galaxy stellar masses derived from CIGALEfitting to the J-PLUS photospectra (Arizo et al. in prep.), the AGNluminosity and radio-loudness distribution, and the presence of starswith activity at radio frequencies. J-HERTZ is publicly availablethrough the J-PLUS DR3 online repository.