Speaker: Daniel Thomas (reader)

We study the redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS. We confirm previous findings that sizes decrease with increasing redshift while internal velocities increase. We show that as a result the dynamical to stellar mass ratios of massive galaxies increase as a function of look-back time up to epochs when the Universe was only a few billion years old. This implies that the dark matter fraction in the centres of galaxies has been increasing with cosmic time for most of the evolution of the Universe. This result is in line with cold dark matter simulations that predict such evolution caused by minor merger driven mass growth.