Weak gravitational lensing

What is gravitational lensing?

Gravitational lensing is a phenomenon where gravity deflects light, causing distortion in the images of distant galaxies as the light is perturbed on its way to the observer. When this distortion is weak, it’s referred to as weak lensing.

The pattern and magnitude of this distortion are closely linked to the distribution of matter in the Universe. As a result, cosmologists analyze the shapes of galaxies to derive key cosmological parameters, advancing our understanding of the cosmos.

Cosmic shear

One method cosmologists use to extract information from this shape distortion is cosmic shear, which involves two-point correlation functions of galaxy shapes to summarize statistical insights into matter distribution.

However, meaningful results depend on carefully addressing unwanted astrophysical effects and observational systematics, which requires substantial effort and precision.