Connecting observations of the first galaxies and the Epoch of Reionisation

Our knowledge of the statistics high redshift galaxies responsible for reionising the Universe is constantly improving and will take yet another important step forward with future facilities. At the same time, the upper limits on the EoR 21cm power spectrum are continually falling, with a firm measurement from SKA-low being a certainty in coming years. In order to maximise what we can learn from these two complimentary observational datasets, we need to be able to model them together, self-consistently. In this talk, I will present insights into the connection between early galaxy formation and the EoR gained from the DRAGONS suite of semi-analytic and hydrodynamic galaxy formation simulations. Using these we find that the steep faint end slope of the the high-redshift galaxy UV luminosity function extends well beyond current observational limits, indicating that only ~50% of the ionising photons available for reionisation have been observed at z<7. I will also demonstrate how the topology of reionisation and associated 21cm signal is sensitive to the properties of high-z galaxies, and discuss how SKA-low, in tandem with other future facilities, will allow us to discriminate between different galaxy formation scenarios.