Astrophysics Seminar

Star formation in galaxies is governed by a complex interplay of nonlinear physical processes operating within the interstellar medium (ISM). Despite this underlying complexity, observations reveal robust scaling relations that point to the remarkably inefficient conversion of gas into stars—suggesting the presence of a self-regulating mechanism. In the local Universe, a coherent picture has emerged over the past decade in which stellar feedback from massive stars and star clusters acts as this regulating agent, shaping the ISM through multiple channels including radiation, winds, and supernovae. 

In this talk, I will first review our current understanding of feedback-regulated star formation under conditions typical of nearby galaxies. I will then turn to more extreme environments—such as those inferred from galaxies at Cosmic Dawn observed with JWST—where the interplay between star formation and feedback, and its implications, remain less well understood. I will outline the unique modelling challenges presented by this regime, particularly the need for coupled radiation hydrodynamics, and describe the novel tools we have developed to address these technical barriers.I will present key insights from state-of-the-art radiation hydrodynamical simulations that probe the competition between feedback and star formation in the early Universe. These results shed light on the efficiency of star formation, the dynamical state of the ISM, and the drivers of cosmic reionization under high-redshift conditions. I will complement these findings with intuitive, physically motivated interpretations based on analytical expectations tailored to the distinct conditions at high redshift. I will conclude by placing these results within the broader context of early galaxy formation, highlight the critical—yet unconstrained—role of the initial mass function (IMF) at these epochs, and present our ongoing efforts to quantify the nature of the IMF at these epochs.