Redshift Drift, Position Drift and Caustics in General Relativity

Explore the intricacies of redshift drift, position drift, and caustics in general relativity through this comprehensive lecture by Prof. Mikołaj Korzyński from the Center for Theoretical Physics, Polish Academy of Sciences. Delve into the temporal variations of redshift and sky position of light sources as observed in relativistic contexts. Examine the derivation of exact relativistic formulas for these drifts, expressed in terms of kinematic variables characterizing source and observer motions, including 4-velocities, 4-accelerations, and spacetime curvature along the line of sight. Gain insights into the physical consequences of these formulas, particularly in spacetimes with caustics, and discover their potential applications in gravitational lensing theory, astrometry, and cosmology. Suitable for those with a basic background in relativity, this talk draws from a graduate course delivered at the Astrophysical Relativity School in Chęciny 2023.