<p>Check out the <a href="http://bogdan.massclean.org/massclean.html" rel="nofollow noreferrer">MASSCLEAN</a> package, it can be used to generate artificial/synthetic clusters of arbitrary metallicities, ages, mass, radius (based on a King profile distribution) and even includes field stars contamination.</p>

<p>Here's an example of a cluster generated with the code (right) imitating a known cluster (NGC 3603, left):</p>

<p><img src="https://i.sstatic.net/Uz5Bp.jpg" alt="enter image description here"></p>

<p>See the <a href="http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:0811.4210" rel="nofollow noreferrer">original article</a> for a good description of the capabilities of the code.</p>

CC BY-SA 3.0
2015-05-20T20:06:38.860Z
That does look handy. How is the field star contamination handled?
ProfRob
CC BY-SA 3.0
2015-05-20T20:12:52.673Z
It can generate an artificial one (based on the model presented in http://adsabs.harvard.edu/abs/1992ApJS...83..111W & http://adsabs.harvard.edu/abs/1994AJ....107..582C) or it can include a real stellar field.  More details in Sect 2.5 of the original article.
Gabriel
CC BY-SA 3.0
2015-05-20T19:24:33.593Z
2015-05-20T20:05:26.667Z
2015-05-20T20:05:26.667Z
Gabriel
<p>The usual thing is a <a href="http://adsabs.harvard.edu/abs/1966AJ.....71...64K" rel="nofollow">King model</a>.</p>

<p>There are indeed free parameters. These are the central density, the "core radius" and a tidal truncation radius.</p>

<p>The background and rationale for these models is given in the link. They provide a pretty good representation of the surface density of globular clusters (or indeed open clusters). They require a numerical scheme to "deproject" from the plane of the sky to 3D.</p>

<p>If you find the nitty-gritty of Abel integrals too tricky in the deprojection, then you could always approximate with a <a href="http://en.wikipedia.org/wiki/Plummer_model" rel="nofollow">Plummer model</a>. This is analytically and computationally easier to deal with, but lacks a bit of physical realism. Central density and a characteristic radius are free parameters here.</p>

CC BY-SA 3.0
2015-05-21T11:39:16.057Z
My needs are pretty simple. I will use the Plummer model.
John
CC BY-SA 3.0
2015-05-20T15:28:34.253Z
2015-05-20T16:58:38.550Z
2015-05-20T16:58:38.550Z
ProfRob
<p>Context: I want to simulate globular clusters in a simple way, just to display the positions of stars. </p>

<p>Assuming isotropy, what would be a reasonable model of the stellar number density as a function or r, the distance from the center of the cluster?</p>

<p>I'm assuming that such a model would have some free parameters as well.</p>

<globular-clusters>
Globular cluster star density as a function of distance from the center
John
# Globular cluster star density as a function of distance from the center

(Asked by: username_0 on 2015-05-20)

Context: I want to simulate globular clusters in a simple way, just to display the positions of stars.

Assuming isotropy, what would be a reasonable model of the stellar number density as a function or r, the distance from the center of the cluster?

I'm assuming that such a model would have some free parameters as well.

**Tags:** globular-clusters

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## 2 answers

### Answer by username_2 on 2015-05-20. Score: 4 | Accepted answer

The usual thing is a [King model](http://adsabs.harvard.edu/abs/1966AJ.....71...64K).

There are indeed free parameters. These are the central density, the "core radius" and a tidal truncation radius.

The background and rationale for these models is given in the link. They provide a pretty good representation of the surface density of globular clusters (or indeed open clusters). They require a numerical scheme to "deproject" from the plane of the sky to 3D.

If you find the nitty-gritty of Abel integrals too tricky in the deprojection, then you could always approximate with a [Plummer model](http://en.wikipedia.org/wiki/Plummer_model). This is analytically and computationally easier to deal with, but lacks a bit of physical realism. Central density and a characteristic radius are free parameters here.

> **Comments:**
> **username_0**: My needs are pretty simple. I will use the Plummer model.  

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### Answer by username_1 on 2015-05-20. Score: 4

Check out the [MASSCLEAN](http://bogdan.massclean.org/massclean.html) package, it can be used to generate artificial/synthetic clusters of arbitrary metallicities, ages, mass, radius (based on a King profile distribution) and even includes field stars contamination.

Here's an example of a cluster generated with the code (right) imitating a known cluster (NGC 3603, left):

![enter image description here](https://i.sstatic.net/Uz5Bp.jpg)

See the [original article](http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:0811.4210) for a good description of the capabilities of the code.

> **Comments:**
> **username_2**: That does look handy. How is the field star contamination handled?  
> **username_1**: It can generate an artificial one (based on the model presented in http://adsabs.harvard.edu/abs/1992ApJS...83..111W & http://adsabs.harvard.edu/abs/1994AJ....107..582C) or it can include a real stellar field.  More details in Sect 2.5 of the original article.  

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