# Is ram-pressure stripping an efficient mechanism to remove gas in galaxies?

## TL;DR

This study uses cosmological simulations to investigate how effectively ram-pressure stripping removes gas from galaxies in clusters, revealing complex gas flows and a less dramatic impact than previously thought.

## Contribution

It provides a detailed analysis of gas dynamics in cluster galaxies, highlighting the limited efficiency of ram-pressure stripping and the ongoing gas accretion from the ICM.

## Key findings

- Gas removal is significant mainly in massive, inner-cluster galaxies.
- Galaxies experience complex gas flows, turbulence, and continuous gas fueling.
- The overall impact of ram-pressure stripping is less dramatic than earlier models suggested.

## Abstract

We study how the gas in a sample of galaxies (M* > 10e9 Msun) in clusters, obtained in a cosmological simulation, is affected by the interaction with the intra-cluster medium (ICM). The dynamical state of each elemental parcel of gas is studied using the total energy. At z ~ 2, the galaxies in the simulation are evenly distributed within clusters, moving later on towards more central locations. In this process, gas from the ICM is accreted and mixed with the gas in the galactic halo. Simultaneously, the interaction with the environment removes part of the gas. A characteristic stellar mass around M* ~ 10e10 Msun appears as a threshold marking two differentiated behaviours. Below this mass, galaxies are located at the external part of clusters and have eccentric orbits. The effect of the interaction with the environment is marginal. Above, galaxies are mainly located at the inner part of clusters with mostly radial orbits with low velocities. In these massive systems, part of the gas, strongly correlated with the stellar mass of the galaxy, is removed. The amount of removed gas is sub-dominant compared with the quantity of retained gas which is continuously influenced by the hot gas coming from the ICM. The analysis of individual galaxies reveals the existence of a complex pattern of flows, turbulence and a constant fuelling of gas to the hot corona from the ICM that could make the global effect of the interaction of galaxies with their environment to be substantially less dramatic than previously expected.