Astrophysics & Particle Physics-APPC 2026

Baryon Acoustic Oscillations, or BAO, represent the lingering traces of sound waves that once moved through the dense plasma in the early universe. These waves didn’t just vanish; they imprinted a specific scale into the arrangement of galaxies we see today. This imprint acts as a “cosmic standard ruler,” an essential reference point for cosmologists to chart the universe’s expansion history and pin down critical parameters, such as the nature of dark energy. This session will delve into the underlying physics of BAO, as well as the observational methods used to detect them ranging from extensive galaxy surveys to analysis of the cosmic microwave background. Additionally, we’ll discuss the growing role of BAO in precision cosmology, highlight major recent findings from prominent surveys, and consider emerging strategies aimed at deepening our insight into the universe’s vast large-scale structure.