Galaxies are hosted by huge dark matter halos in general. In contrast to this consensus, dark matter-deficient galaxies (DMDGs) have been discovered recently. The existence of DMDGs challenges our understanding of galaxy formation, suggesting that DMDGs may be a key to revealing the galaxy formation and the nature of dark matter.
Several theories have attempted to solve the puzzle of the origin of DMDGs and have shown that high density environment could affect the dark matter ratio in a galaxy.
The purpose of the study is to search for more observational evidence of environment effects to dark matter in galaxies from the Sloan Digital Sky Survey data and reveal their properties. The dark matter abundance is determined by the stellar mass to dynamical mass ratio in this study. Further results will be covered in the presentation.