When can globular clusters be considered collisionless?

In summary, the conversation discusses the use of a software package designed for collisionless dynamics to investigate general globular clusters, and whether or not it would be appropriate to use for highly collisional clusters. The person asks for suggestions for alternative software that can be run on a single high-performance PC if using the collisionless package is not feasible. The conversation also touches on the concept of legality in scientific research.
  • #1
kderakhshani
13
0
Hi all.

I'd like to use a software package, that has been designed for collisionless dynamics, to investigate general globular clusters. As they are highly collisional, at least in their inner parts, this perhaps makes no sense.

However, it may be meaningful for some time- or length-scales or to obtain their global properties, such as luminosity, velocity dispersion, etc.

Do you have any idea?

If that is anyway illegal, what software do you suggest that can be run on a single high-performance PC?
( I mean without having PC clusters, GPUs, GRAPE, supercomputers, etc.)

Thanks a lot.
 
Astronomy news on Phys.org
  • #2
Are you asking us to suggest a software package to you?
 
  • #3
The code I used for some globular cluster (NGC 2419) was NMODY, which had been written for COLLISIONLESS stellar systems. For NGC 2419 it is legal, cause its relaxation time is very long (longer than the Hubble time). (K.Derakhshani, ApJ, 783, 48, 2014)

Now, I want to use it (or some other collisionless code) for the total range of Galactic globular clusters.

Under what conditions (if any) will this be legal?

If none, what other software do you suggest to me that can be run on a single PC?

Thanks.
 
  • #4
kderakhshani said:
Under what conditions (if any) will this be legal?

Your word use here is slightly confusing. 'Legal' usually means that something isn't against the law or rules. Are you asking under what conditions this software would be appropriate to use and give good results?
 
  • #5
@Drakkith
Thank you for your comment.
In a wider prospect "legal" means "concordance with the rules of the game". In scientific workss it stands for "not violating the discipline, some scientific law, etc.". For example, if something violates the LAW of conservation of linear momentum, it will be "ILLEGAL".

Anyway, you got it. Do you have any answer to my question?
Thanks
 

1. What is a globular cluster?

A globular cluster is a spherical collection of stars, ranging in size from thousands to millions of stars, that are held together by gravity. They are typically found in the outer regions of galaxies and are some of the oldest known objects in the universe.

2. What does it mean for a globular cluster to be collisionless?

When a globular cluster is considered collisionless, it means that the individual stars within the cluster are not interacting with each other through collisions. Instead, they are only affected by the overall gravitational forces of the cluster as a whole.

3. How can we determine if a globular cluster is collisionless?

Scientists use various techniques, such as computer simulations and observations, to study the motions of stars within a globular cluster. By analyzing the distribution and velocities of the stars, they can determine if the cluster is collisionless or if there is evidence of interactions between stars.

4. What impact does the collisionless nature of globular clusters have on their evolution?

The collisionless nature of globular clusters allows them to maintain their spherical shape and prevent the merging of stars. This allows them to remain relatively unchanged for billions of years, making them important objects for studying the early universe and the dynamics of galaxies.

5. Can a globular cluster ever become collisional?

While globular clusters are primarily considered collisionless, there are instances where interactions between stars can occur, leading to a collisional state. This can happen if the cluster is near a massive object, such as a galaxy, or if it undergoes a core collapse. However, these instances are rare and the overall collisionless nature of globular clusters remains intact.

Similar threads

Replies
1
Views
786
Replies
2
Views
1K
Replies
19
Views
3K
  • Astronomy and Astrophysics
Replies
1
Views
2K
  • STEM Academic Advising
Replies
13
Views
2K
  • Special and General Relativity
Replies
13
Views
2K
  • Computing and Technology
2
Replies
44
Views
11K
  • STEM Academic Advising
Replies
10
Views
4K
Back
Top