The research area "edge-on" typically refers to observational studies of galaxies viewed edge-on from our perspective on Earth. When a galaxy is viewed edge-on, its disk structure is oriented perpendicular to our line of sight, revealing a different perspective of its shape and structure compared to face-on views. This research area often focuses on studying the distribution of stars, gas, and dust within these galaxies, as well as investigating the presence of features such as dust lanes, spiral arms, and bulges. Through studying edge-on galaxies, astronomers can gain insights into the dynamics and evolution of galaxies, as well as the processes of star formation and the formation of galactic structures.