What does the temperature of gas between galaxies in clusters indicate about the cluster mass?

The temperature of gas between galaxies in clusters is directly related to the kinetic energy of the gas particles, which informs us about their speed. In astrophysical terms, hotter gas corresponds to faster-moving particles. The relationship is grounded in the principles of thermodynamics, where temperature is a measure of the average kinetic energy of particles in a system.

When examining galaxy clusters, the temperature of the intergalactic gas can reveal insights into the cluster's gravitational potential and, consequently, its mass. Higher temperature gas indicates a stronger gravitational pull, suggesting that the cluster contains more mass, including both visible and dark matter components. Therefore, measuring the gas temperature is a critical method for estimating the total mass of the cluster.

The other options, while related to different aspects of astrophysics, do not directly tie the temperature of intergalactic gas to mass estimation in the same way. For example, gas density is influenced by many factors beyond temperature, dark matter distribution does not correlate solely with gas temperature, and the age of a galaxy primarily relates to its formation history and not directly to gas temperature dynamics. Thus, the temperature of the gas directly influences the speed of gas particles, which in turn provides information about the mass of the cluster.