protogalaxies

Protogalaxies are theorized early stages in the formation of galaxies. These are thought to be dense concentrations of gas and dark matter that existed in the early universe, long before fully formed galaxies as we observe them today. The prevailing cosmological model, Lambda-CDM, suggests that structure formation in the universe begins with small density fluctuations. These fluctuations in the early universe would have attracted surrounding matter, primarily dark matter, which provides the gravitational scaffolding. As these dark matter halos grew, they would have pulled in primordial gas, predominantly hydrogen and helium. Within these gas-rich halos, gravitational collapse would have initiated. This collapse would lead to the formation of stars, and the accumulation of these stars and gas would eventually give rise to the first protogalaxies. Observing protogalaxies directly is extremely challenging due to their immense distance and the faintness of their emissions in the early universe. However, astronomers look for indirect evidence, such as the light from the very first stars forming within these structures or the spectral signatures of gas at these early cosmic epochs. The study of protogalaxies is crucial for understanding the initial conditions and evolutionary pathways that led to the diverse galaxy populations observed in the present-day universe.