Virial thereom as applied to clusters of galaxies

In summary, the conversation is about the applicability of the virial theorem to clusters of galaxies and how it is not effective due to the small number of member galaxies. However, there is still a way to estimate the masses of member galaxies using their rotation curves. The conversation also includes a brief mention of the speaker's qualifications.
  • #1
alantheastronomer
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I'd just like to comment if I may - The virial thereom is not applicable to clusters of galaxies as the numbers of member galaxies in the majority of clusters (as opposed to superclusters) are too small for the virial thereom to effectively calculate the cluster mass. There is a short article to that effect by Marc Davis from UC Berkeley in the Astrophysical Journal circa 1983. Masses of member galaxies can still be estimated using their rotation curves however...
 
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  • #2
alantheastronomer said:
I'd just like to comment if I may - The virial thereom is not applicable to clusters of galaxies as the numbers of member galaxies in the majority of clusters (as opposed to superclusters) are too small for the virial thereom to effectively calculate the cluster mass. There is a short article to that effect by Marc Davis from UC Berkeley in the Astrophysical Journal circa 1983. Masses of member galaxies can still be estimated using their rotation curves however...
Welcome to the forum.

Putting such a post here in the intro section, where what you were SUPPOSED to put was an actual intro to yourself, is fairly pointless since, although such an intro is a requirement, it is not much looked at. If you want to generate an actual discussion, you should post in the appropriate forum.
 
  • #3
Here's my intro - I have a Masters in Physics from Adelphi University and a Master's in Astrophysics from the University of Illinois at Urbana-Champaign. I'm currently not affiliated with any institution.
 

1. What is the Virial theorem as applied to clusters of galaxies?

The Virial theorem is a mathematical relationship that describes the equilibrium state of a system of particles, such as a cluster of galaxies. It states that the total kinetic energy of the particles in the system is equal to half of the total potential energy.

2. How is the Virial theorem used to study clusters of galaxies?

The Virial theorem is used to study clusters of galaxies by analyzing the motions of the galaxies within the cluster. By measuring the velocities and distances of the galaxies, scientists can calculate the total kinetic and potential energies of the system and determine if it is in equilibrium.

3. What can we learn from applying the Virial theorem to clusters of galaxies?

By applying the Virial theorem to clusters of galaxies, scientists can learn about the mass and distribution of matter within the cluster. This can provide insights into the formation and evolution of galaxies and the large-scale structure of the universe.

4. Are there any limitations to using the Virial theorem for studying clusters of galaxies?

One limitation of using the Virial theorem for studying clusters of galaxies is that it assumes the system is in equilibrium, which may not always be the case. Additionally, it does not take into account the effects of dark matter, which makes up a significant portion of the mass of clusters of galaxies.

5. How does the Virial theorem support the theory of dark matter?

The Virial theorem supports the theory of dark matter by showing that the mass of clusters of galaxies is much larger than what can be accounted for by the visible matter. This indicates the presence of a significant amount of invisible matter, or dark matter, within the clusters.

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