The Effect of colliding galaxies on star formation rates based on IllustrisTNG

Abstract

Galaxy collisions are a complex and common cosmic phenomenon that attracts attention of plenty of scholars. In this paper, the effect of colliding galaxies on the star formation rates will be investigated based on IllustrisTNG, considering three properties of colliding galaxies: distance, velocity and mass. According to the analysis, the deeper the galaxies collide, the larger the SFR values they have. Besides, the effect of collisional and tidal forces on the SFR is continuous. In collisions, galaxies with high relative velocity have higher SFR values compared to galaxies with low velocity; the lighter galaxies have higher SFR values and are more pronounced as the mass ratio of the two galaxies becomes larger. When the colliding galaxies are close in mass, the collision does not have a significant effect on the SFR of both sides. In connection with these results, the possible reasons are discussed for the changing of the SFR by galaxy collisions, i.e., galaxy collisions lead to structural instability of gas clouds in galaxies, causing star formation. These results shed light on guiding further exploration of star formation.