Radio properties of the LOFAR lmETG sample

We set a limit of <~1% to the fraction of remnant or restarted objects, which is <~16% of the extended sources. We found that the properties of the radio sources are connected with the stellar mass of the ETGs (the median radio power, the fraction of extended radio sources, and the link with the large-scale environment). However, these results only describe statistical trends because the radio properties of sources of similar stellar mass and environment show a large spread of radio properties.

These trends break at the lowest host luminosities (M_K_>-24.5). This effect is strengthened by the analysis of even less massive ETGs, with -23.5<M_K_<-21.5. This suggests that at a mass of ~2x10^11^M_{sun}_, a general transition occurs from radio emission produced from radio-loud active galactic nuclei (AGN) to processes related to the host galaxy and (or) radio quiet AGN.

At this luminosity, a transition in the stellar surface brightness profile also occurs from Sersic galaxies to those with a depleted stellar core, the so-called core galaxies. This finding is in line with previous results that indicated that only core galaxies host radio-loud AGN.