When can globular clusters be considered collisionless?

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SUMMARY

The discussion centers on the applicability of collisionless dynamics software for studying globular clusters, specifically questioning the conditions under which such software can yield valid results. The user mentions NMODY, a code designed for collisionless stellar systems, which has been successfully applied to the globular cluster NGC 2419 due to its long relaxation time. The conversation highlights the need for clarity on the term "legal" in a scientific context, emphasizing adherence to scientific principles rather than legal restrictions. The user seeks recommendations for software that can be utilized on a single high-performance PC for broader analysis of Galactic globular clusters.

PREREQUISITES
  • Understanding of collisionless dynamics in astrophysics
  • Familiarity with NMODY software for stellar dynamics
  • Knowledge of globular cluster properties, such as relaxation time and luminosity
  • Basic computational skills for running simulations on high-performance PCs
NEXT STEPS
  • Research the application of NMODY for various globular clusters beyond NGC 2419
  • Explore alternative collisionless dynamics software suitable for single PC use
  • Investigate the implications of relaxation time on the validity of collisionless models
  • Study the principles of conservation laws in astrophysical simulations
USEFUL FOR

Astronomers, astrophysicists, and researchers interested in the dynamics of globular clusters and the application of computational models in astrophysics.

kderakhshani
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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.
 
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Are you asking us to suggest a software package to you?
 
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.
 
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?
 
@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
 
https://en.wikipedia.org/wiki/MoM-z14 Any photon with energy above 24.6 eV is going to ionize any atom. K, L X-rays would certainly ionize atoms. https://www.scientificamerican.com/article/whats-the-most-distant-galaxy/ The James Webb Space Telescope has found the most distant galaxy ever seen, at the dawn of the cosmos. Again. https://www.skyatnightmagazine.com/news/webb-mom-z14 A Cosmic Miracle: A Remarkably Luminous Galaxy at zspec = 14.44 Confirmed with JWST...

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