Ram Pressure Stripping

Definition

Ram pressure stripping is a process that occurs in galaxy clusters where the hot, diffuse gas between galaxies, known as the intracluster medium (ICM), exerts a force on the interstellar medium (ISM) of a galaxy as it moves through the cluster. This force can remove the gas from the galaxy, stripping it of its fuel for star formation.

5 Must Know Facts For Your Next Test

1. Ram pressure stripping can significantly impact the evolution of galaxies in dense environments, such as galaxy clusters, by removing their gas supply and quenching star formation.
2. The strength of the ram pressure force depends on the density of the intracluster medium and the velocity of the galaxy moving through it, with faster-moving galaxies experiencing stronger ram pressure.
3. Galaxies with lower gravitational potentials and less dense interstellar media are more susceptible to ram pressure stripping, as the force can more easily overcome the galaxy's ability to retain its gas.
4. Ram pressure stripping can lead to the formation of long, trailing tails of stripped gas and dust, which can be observed in some cluster galaxies and provide evidence of this process.
5. The removal of gas from galaxies due to ram pressure stripping can also trigger the formation of new stars in the stripped material, leading to the creation of so-called 'jellyfish galaxies' with distinctive tails.

Review Questions

• Explain how the ram pressure exerted by the intracluster medium can affect the evolution of galaxies in a galaxy cluster.
  • The ram pressure exerted by the hot, diffuse gas in the intracluster medium can strip away the interstellar medium of a galaxy as it moves through the cluster. This removal of the galaxy's gas supply can significantly impact its evolution by quenching star formation, as the galaxy is deprived of the fuel necessary to continue forming new stars. The strength of the ram pressure force depends on the density of the intracluster medium and the velocity of the galaxy, with faster-moving galaxies experiencing stronger ram pressure. Galaxies with lower gravitational potentials and less dense interstellar media are more susceptible to this stripping process, which can lead to the formation of distinctive tails of stripped gas and dust.
• Describe the characteristics of 'jellyfish galaxies' and explain how they are related to the process of ram pressure stripping.
  • Jellyfish galaxies are a class of galaxies that exhibit long, trailing tails of stripped gas and dust, a result of the ram pressure stripping process. These tails are formed when the hot, diffuse gas in the intracluster medium exerts a force on the interstellar medium of the galaxy, effectively removing the gas supply as the galaxy moves through the cluster. The removal of this gas can trigger the formation of new stars in the stripped material, leading to the distinctive 'jellyfish-like' appearance of these galaxies. Jellyfish galaxies provide direct observational evidence of the ram pressure stripping process and its impact on the evolution of galaxies in dense cluster environments.
• Analyze how the characteristics of a galaxy, such as its gravitational potential and the density of its interstellar medium, can influence its susceptibility to ram pressure stripping in a galaxy cluster.
  • The susceptibility of a galaxy to ram pressure stripping in a galaxy cluster is heavily influenced by the galaxy's own characteristics, particularly its gravitational potential and the density of its interstellar medium. Galaxies with lower gravitational potentials and less dense interstellar media are more easily affected by the ram pressure exerted by the hot, diffuse gas in the intracluster medium. This is because the ram pressure force can more easily overcome the galaxy's ability to retain its gas supply, leading to the stripping of the interstellar medium. In contrast, galaxies with higher gravitational potentials and denser interstellar media are more resistant to the ram pressure, and are less likely to experience significant gas loss and the resulting quenching of star formation. Understanding these galaxy-specific factors is crucial for analyzing the impact of ram pressure stripping on the evolution of different types of galaxies within a cluster environment.

Related terms

Intracluster Medium (ICM): The hot, diffuse gas that fills the space between galaxies in a galaxy cluster, which can exert ram pressure on the interstellar medium of a galaxy.

Interstellar Medium (ISM): The gas and dust between stars within a galaxy, which can be stripped away by the ram pressure of the intracluster medium.

Galaxy Clusters:

Large, gravitationally bound groups of galaxies that contain hot, diffuse gas in the space between the galaxies, which can lead to ram pressure stripping.