Extragalactic astronomy is the branch of astronomy that focuses on the study of celestial objects and phenomena that are located outside of the Milky Way galaxy. This includes galaxies, galaxy clusters, quasars, and other objects that are located billions of light years away from Earth. Extragalactic astronomy aims to understand the structure, evolution, and dynamics of these distant objects, as well as their interactions with each other and their impact on the universe as a whole. Researchers in this field use a variety of observational techniques, such as telescopes, spectroscopy, and imaging, to study and analyze these extragalactic objects and unravel the mysteries of the universe beyond our own galaxy.