Velocity Dispersion: Meaning & Difference Explained

In summary, the conversation discusses the concept of velocity dispersion in galaxies and the difference between stellar velocity dispersion and molecular velocity dispersion. The conversation also references a paper that mentions the ratio of stellar to gas velocity dispersion. The specific questions asked are about the two types of velocity dispersion and their differences.
  • #1
J Azeez
2
0
What does mean by velocity dispersion of galaxy? What is the different between stellar velocity dispersion and molecular velocity dispersion?
 
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  • #2
J Azeez said:
What does mean by velocity dispersion of galaxy? What is the different between stellar velocity dispersion and molecular velocity dispersion?
Welcome to the PF. :smile:

Please post links to the reading you have been doing about those terms, and then ask specific questions about that reading if you are having trouble understanding something in your links.
 
  • #3
In this paper the author mentioned " the ratio of stellar to gas velocity dispersion "
I understand from that there are two types of velocity dispersion , am I right? if so what is the different between them?
 

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  • THE PROPERTIES OF THE STAR-FORMING INTERSTELLAR MEDIUM AT.pdf
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1. What is velocity dispersion?

Velocity dispersion refers to the measure of the spread of velocities within a system, such as a group of stars or galaxies. It is commonly used in astrophysics to understand the dynamics and structure of these systems.

2. How is velocity dispersion different from average velocity?

While average velocity is a measure of the average speed of objects within a system, velocity dispersion takes into account the spread or distribution of velocities within the system. It provides a more comprehensive understanding of the motion of objects in a system.

3. What is the significance of velocity dispersion in astronomy?

Velocity dispersion is an important parameter in understanding the formation and evolution of galaxies, clusters of galaxies, and other large-scale structures in the universe. It can also provide insights into the amount and distribution of dark matter within these systems.

4. How is velocity dispersion measured?

Velocity dispersion is typically measured through spectroscopic observations, which measure the Doppler shifts of light emitted by objects in a system. The broader the range of velocities observed, the larger the velocity dispersion.

5. Can velocity dispersion be used to determine the age of a system?

No, velocity dispersion alone cannot determine the age of a system. It is influenced by various factors such as the mass and size of the system, so it cannot be used as a direct measure of age. However, it can provide valuable information about the dynamics and structure of a system, which can be used in conjunction with other data to estimate its age.

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