Astrophysics & Particle Physics-APPC 2026

Large-Scale Structure (LSS) of the universe is the extended web of matter that fills hundreds of millions of light-years, shaping galaxies, galaxy clusters, filaments, voids, and superclusters. It is the matter arrangement on the biggest cosmic scales and is a basic feature of cosmology and astrophysics.The LSS is determined by gravitational interactions, dark matter distribution, and the expansion of the cosmos. Galaxies are not distributed randomly; they occur in complex patterns within the cosmic web, with clusters and filaments of high density separated by huge voids. CMB observations give insight into the large-scale structure of dark matter and the effects of dark energy on cosmic expansion.Large redshift surveys like the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey (DES) are used to study LSS, where galaxy positions and motions are mapped to show clustering patterns, filaments, and voids. These observations help test cosmological models and understand how structures evolved from the tiny fluctuations observed in the cosmic microwave background (CMB) to the complex structures seen today.The formation of LSS is closely linked to galaxy formation and evolution. Gravity causes matter to collapse into denser regions, forming halos of dark matter that host galaxies and clusters.

The interaction between baryonic matter, dark matter, and dark energy governs the growth and evolution of structure across cosmic time.The knowledge of the LSS gives insights into the basic physics, such as the nature of dark matter and dark energy, the laws of gravity, and the history of the universe. By studying galaxy clustering, filament connectivity, and void statistics, astronomers are able to constrain cosmological parameters and examine the large-scale dynamics of the universe.The Large-Scale Structure is a pillar of contemporary cosmology, showing how the universe went from a state that was almost uniform after the Big Bang into a finely structured cosmic web, linking theoretical predictions with observational astronomy and enabling scientists to comprehend the architecture and evolution of the universe.