Seminarium Teorii Względności i Grawitacji

Gravitational collapse is a physical process that begins when an object's outward pressure—whether that of a star, galaxy, or a dust cloud—fails to counteract its own self-gravity. Without gravitational collapse in an ever-expanding Universe, there would be no stable dense objects in the sky: no stars, nebulas, galaxies, or black holes. Among the various collapse scenarios studied, the gravitational collapse of real scalar fields holds particular interest due to its dual appeal: its mathematical simplicity and its ability to model realistic matter fields in Cosmological and Astrophysical phenomena. This talk will provide a comprehensive overview of the possible end-states, both singular and regular, arising from such collapses. In the first part, I will discuss the unhindered collapse of scalar fields, exploring the nature of the resulting singularities and their physical viability, including whether they are visible or hidden from external observers. In the second part, I will explain how introducing specific non-zero potentials can halt the collapse, leading to the formation of regular end-states. Finally, I will highlight the relevance of these regular end-states in a Cosmological context.