Speaker
Description
The evolution of active galactic nuclei (AGN) is closely connected to their host galaxies and surroundings. Via feedback processes, AGN can counteract the cooling of the intracluster medium and suppress star formation in their host galaxies. Especially radio observations at low frequencies are able to provide a glimpse into the history of AGN activity, due to the ability to trace old AGN emission. The Virgo cluster, as a substantial reservoir of nearby galaxies, provides an ideal laboratory to study these mechanisms.
To this end we analysed the ACSVCS sample of 100 Virgo cluster early-type galaxies, using unique LOFAR and MeerKAT observations which cover the entire Virgo cluster. The aim of our work was to characterise the AGN population within the Virgo cluster down to low radio luminosities, constrain the AGN duty cycle, and investigate environmental feedback in cluster member galaxies.
In this talk, I will present our results, including a clear correlation between the radio luminosity of AGN and the stellar mass of their host galaxies, as well as indications of a relationship between the angular size and spectral index of the radio emission. I will also discuss two particularly interesting sources, exhibiting very low-surface brightness emission only detectable with LOFAR. For one of those sources - the galaxy M49 - we found an X-ray cavity inflated by its wide-angle tail, which provides new insights into the AGN’s past duty-cyle.
