Caught in the Cosmic Web: Evidence for Ram Pressure Stripping of a Low-mass Galaxy by the Cosmic Web

Abstract We present interferometric radio observations of the neutral atomic gas in AGC 727130, a low-mass, gas-rich field galaxy lacking significant star formation. The atomic gas in AGC 727130 displays a pronounced asymmetry, extending well beyond the stellar disk in one direction while remaining relatively undisturbed in the other. Despite proximity to a pair of interacting dwarfs, tidal analysis suggests these neighboring galaxies are not responsible for this pronounced asymmetry. Instead, using a topological cosmic web filament finder on spectroscopic catalog data, we find AGC 727130 lies at the intersection of several large-scale cosmic web filaments, environments predicted to host diffuse, shock-heated gas. We propose that an interaction with this ambient medium is stripping gas from the galaxy via cosmic web ram pressure stripping. This mechanism, supported by recent simulations, may quench low-mass galaxies outside of massive halos and must be accounted for when comparing observed numbers of dwarf galaxies to theoretical predictions.