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domeckert / pyproffit

Pyproffit is a Python code for the analysis of X-ray brightness profiles from clusters of galaxies
GNU General Public License v3.0
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Question on defining the center point for the model #28

Open ktrehaeven opened 1 month ago

ktrehaeven commented 1 month ago

Hi

I have a quick question...is it possible to make the surface brightness model have two different centers for the different components? I'm specifically talking about a double beta model...can each beta model have a different center and how would you go about doing that if possible?

Kind regards Keegan Trehaeven

domeckert commented 1 month ago

Hi @ktrehaeven . pyproffit is inherently 1D, so it is not possible (at least for the moment) to make a joint fit of two models with different centers. To this end it would be necessary to make a 2D fit; if that is something you are interested in, I would be glad to work with you to implement such a feature.

With the current setup, if what you have in mind is to fit two clumps with different centers, what I would do is to mask the second clump, fit the profile of the first clump (possibly in the opposite direction) and create a 2D model for the first clump using the SaveModelImage method. Then I would add the model to the background model and consider the first clump as background, to then fit the second clump and extract another model image for it. The sum of the two model images should be roughly your 2D model.

ktrehaeven commented 1 month ago

Hi, @domeckert, thank you very much for your reply. A 2D version of your code has already been implemented by Xiaoyuan Zhang et al 2022 ( https://ui.adsabs.harvard.edu/abs/2023A%26A...672A..42Z/abstract) to study the density fluctuations of the LoTTS-DR2. With that code I was able to fit two completely independent beta models in 2D. @xzhang do you want to be a part of this? Kind regards Keegan Trehaeven

On Mon, Oct 28, 2024 at 6:16 PM Dominique Eckert @.***> wrote:

Hi @ktrehaeven https://github.com/ktrehaeven . pyproffit is inherently 1D, so it is not possible (at least for the moment) to make a joint fit of two models with different centers. To this end it would be necessary to make a 2D fit; if that is something you are interested in, I would be glad to work with you to implement such a feature.

With the current setup, if what you have in mind is to fit two clumps with different centers, what I would do is to mask the second clump, fit the profile of the first clump (possibly in the opposite direction) and create a 2D model for the first clump using the SaveModelImage method. Then I would add the model to the background model and consider the first clump as background, to then fit the second clump and extract another model image for it. The sum of the two model images should be roughly your 2D model.

— Reply to this email directly, view it on GitHub https://github.com/domeckert/pyproffit/issues/28#issuecomment-2442034159, or unsubscribe https://github.com/notifications/unsubscribe-auth/ASRMRFEA3NEQKN3Y6TZJU6DZ5ZIMNAVCNFSM6AAAAABQXVA5PWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDINBSGAZTIMJVHE . You are receiving this because you were mentioned.Message ID: @.***>