Astrophysics Seminar

Observations of galaxies reveal a wide range of morphological features and physical properties, which are encoded into Hubble's classification scheme. The morphological evolution of galaxies is primarily driven by gravitational instabilities acting at different scales, through processes such as tidal interactions, mergers, fragmentation of gas disc, turbulence, and feedback. In this talk, I will present a unified model of disc instabilities to explore the influence of dark matter on the stability of self-gravitating galactic discs composed of stars and cold gas.

I will show how gravitational instabilities can explain the observed differences between spiral and irregular galaxies in the local universe, based on their stability levels, gas fractions, and the timescales for growth of instabilities. Finally, I will compare the stability levels in nearby galaxies to those observed at high redshift — the precursors of present-day galaxies — to highlight the role of gravitational instabilities in shaping galaxy evolution.