Astrophysics & Particle Physics-APPC 2026

Gravitational-Wave Astronomy is a cutting-edge branch of astrophysics that searches for ripples in space-time produced by colossal cosmic events. Foreseen by Einstein's General Relativity, gravitational waves are produced by accelerating masses like colliding black holes, neutron stars, or supernovae and travel at the speed of light throughout the universe.The first direct observation of gravitational waves in 2015 by the LIGO observatory launched a new era of astronomy, enabling scientists to see cosmic events invisible to electromagnetic radiation. Follow-up detections made by LIGO, Virgo, and KAGRA have since verified the presence of binary black hole and neutron star mergers, offering unparalleled knowledge of the behavior of compact objects and the extreme physics that rules them.Gravitational-wave astronomy forms a backbone of multi-messenger astrophysics, which brings together gravitational-wave signals and electromagnetic observations, neutrinos, and cosmic rays to explore the same cosmic phenomena in various manners. This method has transformed our knowledge of stellar evolution, black hole creation, neutron star mergers, and the creation of heavy elements.Exquisite detectors quantify tiny curvatures of space-time, necessitating state-of-the-art laser interferometry and razor-sharp instrumentation. Such measurements enable astrophysicists to investigate underlying physics in extreme environments, verify general-relativistic predictions, and study the universe's most powerful events.Gravitational-wave observations also yield important information regarding the cosmic compact-object population, their masses, spins, and merger rates, illuminating the evolution of galaxies and the life cycles of stars.

In addition, research on these waves improves our knowledge of cosmic expansion, dark matter, and the early universe, providing special opportunities to study phenomena that are out of reach for optical and radio telescopes. By opening a new window into observation of the cosmos, gravitational-wave astronomy continues to widen our understanding of the universe, opening a window into the dynamic and violent processes that sculpt the evolution of stars, galaxies, and the space-time fabric itself.