About the project
In the local Universe, galaxies can be broadly classified into discs, ellipticals and irregulars. Discs contain regularly-rotating gas, and are forming new stars. Ellipticals contain predominantly old stars in randomly oriented, round-shaped orbits, don't have much gas and are no longer forming stars. Irregulars are often the result of the merger between two disc galaxies, are rich in gas and dust, and are forming stars at an intense rate.
The dynamics and star formation activity of galaxies in the local Universe is intimately connected to their morphology. This is expected in cosmological models, which indicate that the evolution of galaxies is mainly driven by the giant dark matter “haloes” in which they reside. Indeed, if the gas retains its angular momentum while it collapses within the dark matter halo, this will form a centrifugally-supported disc with an exponential light profile. On the other hand, mergers and/or powerful gas outflows can redistribute the angular momentum and yield an elliptical.
To understand how the connection between morphology, dynamics and star formation in galaxies is established, we need to look at the distant Universe, where most of the present-day stars have been formed. We will conduct an observational project to measure the spatially-resolved gas dynamics, star formation rate and stellar mass distribution in star-forming galaxies at z≳1 or lookback times of ~10 billion years, which corresponds to the epoch when galaxies are most efficient at forming stars and the Universe was about 20% of its current age. We will measure the role of angular momentum, dark matter, mergers, and gas outflows in shaping the relation between morphology, dynamics and star-forming activity in galaxies. We will address the following questions:
- What physical processes regulate star formation in galaxies?
- Are the dynamical properties of galaxies evolving with redshift?
- What is the impact of baryons on dark matter haloes?
The student will use state-of-the-art observations from the largest telescopes available, including JWST and ALMA to measure the mass, distribution and dynamics of stars and gas in distant galaxies. The student will receive training in the reduction and analysis of imaging, integral-field spectroscopy and interferometry. The student will have the possibility to use results from state-of-the-art semi-empirical models developed by our galaxy evolution group in Southampton to interpret the observational results of their project.