Studying galaxy evolution through cosmic time via the μJy radio population: early results from eMERGE
The e-MERLIN Galaxy Evolution Survey (eMERGE) is an ambitious, multi-tiered extragalactic radio continuum survey being carried out with e-MERLIN and the VLA at 1.4GHz and 6 GHz. Exploiting the unique combination of high sensitivity and high angular resolution provided by radio interferometry, these observations will provide a powerful, obscuration-independent tool for tracing intense star-formation and AGN activity in galaxies out to z∼5. In our first data release (DR1) we present eMERGE Tier 1, a 15-arcmin pointing centred on the GOODS-N field, imaged at 1.4GHz with the VLA and e-MERLIN at ∼0.28" resolution down to an rms sensitivy of ∼1.2μJy/beam. This unique radio survey – unrivalled at 1.4 GHz in its combination of depth, areal coverage and angular resolution in the pre-SKA era – allows us to localise and separate extended star-forming regions, nuclear starbursts and compact AGN core/jet systems in galaxies over the past two-thirds of cosmic history, a crucial step in tracing the apparently simultaneous growths of the stellar populations and central black holes in massive galaxies. In these proceedings we highlight some early science results from eMERGE DR1, including some examples of the sub-arcsecond morphologies and cold dust properties of 1.4GHz-selected galaxies. eMERGE Tier 1 will eventually reach sub-μJy/beam sensitivity at 0.28" resolution over a 30-arcmin field, providing crucial benchmarks for deep extragalactic surveys which will be undertaken with SKA in the next decade.