<p>I am computer scientist and now I'm working with some astrophysical projects. During this work I accumulated some questions and maybe here I would be able to find some answers or advice where to look for them. I already read some of the wiki pages on topic, but it didn't help. </p>

<p>We are working with fitting light profiles of some eliptic galaxies with GALPHAT using Sersic and Sersic Exponential models.
1. So first question would be, what exactly means to fit a light profile? I get a bunch of parameters as output (X, Y, Mag, re, n, q and others), but what exactly does it mean? 
2. And the second question is what is the difference between these two models?</p>

CC BY-SA 4.0
2020-04-27T11:47:38.880Z
I'm a bit confused as to what's going on here. You say, "We are working on fitting light profiles ... with GALPHAT ...", but then you say you don't now what "fitting light profiles" means. Do any of your collaborators know what's going on?
Peter Erwin
CC BY-SA 4.0
2020-04-27T11:48:36.827Z
When you say you are using GALPHAT, I assume this is the code of Yoon, Weinberg, & Katz (2010) (https://arxiv.org/abs/1010.1266). Have you tried reading that paper to understand what's going on?
Peter Erwin
CC BY-SA 4.0
2020-04-27T13:56:38.053Z
Hi Peter, yes, I did read this article and several related, but it didn't seem to help much. What I'm trying to understand is more like contextual meaning of it. And about my collaborators, yes, we had some talk, but this was not enough as well, so I'm trying to find more information here while reading articles on the topic.
Igor Kolesnikov
<galaxy><light><photometry><modeling>
Light profile fitting related questions
Igor Kolesnikov
# Light profile fitting related questions

(Asked by: username_0 on 2020-04-26)

I am computer scientist and now I'm working with some astrophysical projects. During this work I accumulated some questions and maybe here I would be able to find some answers or advice where to look for them. I already read some of the wiki pages on topic, but it didn't help.

We are working with fitting light profiles of some eliptic galaxies with GALPHAT using Sersic and Sersic Exponential models.
1. So first question would be, what exactly means to fit a light profile? I get a bunch of parameters as output (X, Y, Mag, re, n, q and others), but what exactly does it mean?
2. And the second question is what is the difference between these two models?

**Tags:** galaxy, light, photometry, modeling

> **Comments:**
> **username_1**: I'm a bit confused as to what's going on here. You say, "We are working on fitting light profiles ... with GALPHAT ...", but then you say you don't now what "fitting light profiles" means. Do any of your collaborators know what's going on?  
> **username_1**: When you say you are using GALPHAT, I assume this is the code of Yoon, Weinberg, & Katz (2010) (https://arxiv.org/abs/1010.1266). Have you tried reading that paper to understand what's going on?  
> **username_0**: Hi Peter, yes, I did read this article and several related, but it didn't seem to help much. What I'm trying to understand is more like contextual meaning of it. And about my collaborators, yes, we had some talk, but this was not enough as well, so I'm trying to find more information here while reading articles on the topic.  

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## 0 answers

