Research Fellows Directory
Professor Michele Cappellari
University of Oxford
Since the beginning of history, humanity has constantly been intrigued with the question of our origin. This has led to a number of scenarios to describe our Universe and position in it. Less than a century ago it has been realized that the Universe is composed of billions of galaxies like the Milky Way, in which we live. For this reason, today, the quest of our origin involves an understanding of how galaxies form and evolve.
There are two complementary approaches to study the formation of galaxies. One can observe nearby objects, which can be analysed in detail due to their vicinity, and contain the fossil record of billions of years of evolution. Or one can observe the distant galaxies whose light reaches us after billions of years of travel through space. For this reason we can see them as they were when the Universe was young and the galaxies were still forming. These two approaches, together with numerical simulations, have provided a scenario, in which the Universe is dominated by a mysterious dark matter (DM) and galaxies grow in mass, in a hierarchical fashion, by the co-addition of smaller pieces, under the influence of gravity.
A fundamental limitation affects the comparisons with the predictions of the models, especially for galaxies at large distances, when the Universe was less than half of its current age. The problem is that, while the simulations directly predict the MASSES of the stars and DM in galaxies, the observations only provide the LUMINOSITY of the stars. The luminosity constitutes the tip of the iceberg of the underlying stellar and DM mass distribution associated to the galaxies.
In this project I am measuring the evolution of the galaxy mass from a time in which the Universe was 1/4 of its current age, to the present day. These new mass measurements will be compared to the mass predictions of galaxy formation models to provide a stringent test of the current hierarchical galaxy formation paradigm.
Interests and expertise (Subject groups)