The Physics and evolution of galaxies in the epoch of re-ionisation

One of the most exciting open problems in Astrophysics is understanding the nature and evolution of the very first galaxies, stars and black holes, but also how they changed the Universe as a whole and ended the dark ages. This PhD project will allow the student to conduct and explore the largest surveys for very distant galaxies (Lyman-alpha emitters) and push them to the highest look back times when the Universe was only 700 Myrs or less. The student will reduce, analyse and explore near-infrared photometric data in the COSMOS field from the recently concluded (100%) Y-NBS survey (PI: Sobral) on the Very Large Telescope in Chile, which had an allocation of 50 hours in excellent observing conditions. The Y-NBS survey is the widest ever conducted for distant bright Lyman-alpha sources, even more distant than the CR7 galaxy (Sobral et al. 2015) and the student is expected to find up to 20 new bright distant galaxies, along with 1000s of other lower redshift starburst galaxies and AGN. The student will also explore our state-of-the-art datasets that have just been obtained with the Hubble Space Telescope, ALMA and with other instruments on the VLT in Chile, to place the newly discovered galaxies into a wider context and test state-of-the-art models. The second part of the project will involve obtaining and exploring follow-up observations, including spectroscopy at a variety of wavelengths with the GTC (on-going program) in La Palma, in order to investigate the physics of the first galaxies. This will involve a close link with photo-ionisation and radiative transfer models and will provide some of the first measurements of the metallicity, ionisation parameters and other properties of early galaxies. The results will provide crucial new information to improve our currently limited understanding of the re-ionisation epoch and how distant bright galaxies may have played a crucial role in such process.