SO Webloquio: Star-formation and accretion in galaxies from near to far: the LeMMINGs and eMERGE e-MERLIN legacy programmes

Radio emission provides a uniquely powerful and unobscured probe of the two key physical processes underway in, and powering, galaxies and their evolution: Accretion on to their central SMBH, and star-formation processes. To explore these processes, and their role in galaxy evolution, we require very high resolution (sub-arcsecond or better), sensitive imaging at radio wavelengths across large samples of galaxies in both the local and distant universe. In this seminar, I will describe the motivation and latest results from two large ‘sister’ e-MERLIN surveys (the 800-hr Legacy e-MERLIN Multi-band Imaging of Nearby Galaxies (LeMMINGs) and 1000-hr e-MERlin Galaxy Evolution (e-MERGE) surveys) which are using the e-MERLIN (the UK’s National Radio Astronomy facility, and an SKA pathfinder instrument) and NRAO’s VLA. These two projects are currently producing some of the deepest (uJy), sub-arcsecond and milliarcsecond resolution radio imaging of ‘normal’ local galaxies (LeMMINGs – surveying 280 nearby galaxies), and ‘extreme’ distant (up to z~5) galaxies (e-MERGE – 1000hr deep survey of the GOODS-N region). In each of these surveys we are able to spatially resolve, at radio wavelengths, the activity powering these galaxies. Combining this with extremely rich multi-wavelength ancillary data these surveys are separating star-formation and accretion at high redshift (allowing analysis of the co-evolution of these processes), and in local galaxies are characterising the role of low-luminosity AGN, providing a key bridge between our understanding between extragalactic AGN sources and accreting galactic blackholes.