15 April: Kenneth Duncan

Speaker: Kenneth Duncan (University of Edinburgh)

Date: Wednesday 15 April 2026

Time: 15:00

Location: Physics 3.29 Access Grid

New spectroscopic studies of the radio Universe

One of the outstanding observational advances in the last decase has been the SKAO pathfinders and precursors reaching maturity to become key facilities across a range of science areas. Parallel to this transformation in radio continuum and HI observations has been the development of a new generation of multi-object spectrographs that have the potential to be equally transformational. 

For all extragalactic radio source populations, this spectroscopy is essential for providing precise redshifts, separating star-formation and AGN activity, identifying accretion modes and revealing detailed host galaxy properties. It is only with the detailed emission line and optical continuum diagnostics from spectroscopy that we can begin to link the AGN and star-formation activity revealed by the radio continuum to the kinematic and chemical histories of galaxies. Furthermore, large samples of precise spectroscopic redshifts are also essential for revealing the detailed evolution of the baryon cycle in galaxies far beyond the limitations of current surveys (through spectral stacking analyses).

Motivated by these needs, the WEAVE-LOFAR Survey on the WEAVE spectrograph in the Northern hemisphere and ORCHIDSS on the 4MOST spectrograph (PI: Duncan) in the Southern hemisphere are two dedicated spectroscopic surveys targeting radio continuum selected populations. After years of planning, survey operations for both are now beginning to ramp up, with science verification activities on-going/completing at the time of this presentation. In addition to presenting a broader background, I will illustrate some of the motivation for these surveys with recent science results from current LOFAR and MeerKAT radio surveys, followed by an overview of science goals, survey plans and earliest results.