Marios Karouzos

Marios Karouzos Colloquium: Galaxies on a diet: feedback signatures in radio-AG

Marsfield Lecture Theatre

Abstract

There exists strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. An important mechanism connecting AGN to their host galaxies is AGN feedback, potentially heating up or even expelling gas from galaxies. AGN feedback may hence be responsible for the eventual quenching of star formation and halting of galaxy growth. A rich multi-wavelength dataset ranging from the X-ray regime (Chandra), to far-IR (Herschel), and radio (WSRT) is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope, covering a total area on the sky of 5.4 sq. degrees. We investigate the star-formation properties and possible signatures of radio feedback mechanisms in the host galaxies of 237 radio sources below redshift z=2 and at a radio 1.4 GHz flux density limit of 0.1 mJy. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied simultaneously as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while also offering evidence showcasing two, potentially competing, links between AGN activity and host galaxy star formation. In particular, I will show results supporting a ``maintenance'' type of feedback from powerful radio-jets. Finally, I will present preliminary results based on the stacking analysis of Herschel far-IR data of the most radio-luminous AGN in the AKARI-NEP field and also offer an outlook for the future exploitation of data from the ATLAS and the planned EMU radio surveys.