Combining ALMA with HST and VLT to Find the Counterparts of Submillimetre Galaxies

The identification of optical/near-infrared counterparts to submillimetre galaxies (SMGs) has been one of the most enduring obstacles in learning more about the nature of these massively star-forming systems, including their true redshift distribution. Various techniques have been partially successful but it is only by imaging the submillimetre (submm) emission at the same angular resolution as the optical images that counterparts can be securely assigned. With ALMA it is now possible to image the redshifted dust emission from these objects with a minimum investment of observing time. The results of an analysis of the properties of the counterparts of ten submm galaxies that fall within the CANDELS coverage of the GOODS-S field is presented. All ten SMGs show homogeneous properties in their dust and gas content, but only eight show (surprisingly) homogeneous properties in terms of the stellar mass and characteristic age of the stellar population. The two deviating counterparts are discussed.