When and How Ram Pressure Stripping in Low-mass Satellite Galaxies Enhances Star Formation

Abstract

We investigate how a satellite's star formation rate (SFR) and surviving gas respond to ram pressure stripping (RPS) in various environments. Using a suite of high-resolution wind tunnel simulations with radiative cooling, star formation, and supernovae feedback, we model the first infall orbit of a low-mass disk galaxy ( M _* = 10 ^9.7 M _⊙ ) in different host halos, ranging from Milky Way–like to cluster hosts. When the ram pressure is moderate, we find that the stripping satellite shows an enhanced SFR relative to the isolated control case, despite gas loss due to stripping. The SFR enhancement is caused, not directly by compression, but by ram-pressure-driven mass flows, which can increase the dense gas fraction in the central disk regions. The spatially resolved star formation main sequence and Kennicutt–Schmidt relations in our simulations are consistent with recent findings of the VERTICO and GASP surveys. Our results predict the environmental signals of RPS in future multiwavelength, high-angular resolution observations: the star formation and gas surface densities will be centralized, and symmetrically enhanced within the stripping radius.

Keywords

• Interstellar medium
• Galaxy interactions
• Star formation
• Hydrodynamical simulations