Strangulation in Galaxy Groups

We use a cosmological chemodynamical simulation to study how the group environment impacts the star formation properties of disk galaxies. The simulated group has a total mass of M ∼ 8 × 10 M⊙ and a total X-ray luminosity of LX ∼ 10 41 erg s. Our simulation suggests that ram pressure is not sufficient in this group to remove the cold disk gas from a Vrot ∼ 150 km s −1 galaxy. However, the majority of the hot gas in the galaxy is stripped over a timescale of approximately 1 Gyr. Since the cooling of the hot gas component provides a source for new cold gas, the stripping of the hot component effectively cuts off the supply of cold gas. This in turn leads to a quenching of star formation. The galaxy maintains the disk component after the cold gas is consumed leading to a galaxy with S0 properties. Our self-consistent simulation suggests that this strangulation mechanism works even in low mass groups, providing an explanation for the lower star formation rates in group galaxies relative to galaxies in the field. Subject headings: galaxies: kinematics and dynamics —galaxies: evolution —galaxies: stellar content —methods: numerical