When and how does ram pressure stripping in low-mass satellite galaxies enhance star formation

TL;DR

This study uses high-resolution simulations to show that moderate ram pressure stripping in low-mass satellite galaxies can enhance star formation by increasing dense central gas, with observable signatures predicted for future surveys.

Contribution

It reveals that ram pressure can boost star formation through gas flows, not just compression, in low-mass satellites during infall, a novel insight into environmental effects.

Findings

Moderate ram pressure enhances SFR despite gas loss.

Enhanced SFR is driven by ram pressure-induced mass flows, not compression.

Simulated spatial relations match recent observational surveys.

Abstract

We investigate how a satellite's star formation rate (SFR) and surviving gas respond to ram pressure stripping 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 ($M_{*} = 10^{9.7} M_{\odot}$) 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.