Add option to exclude local background in residual image (#1690)

[m-samland]

This pull request is to solve issue #1690. I added a new keyword to the function make_model_image' and make_residual_image' of the PSFPhotometry-class to toggle whether the local background model is included or not.

At the moment it is only possible to make a model image of the fitted PSF Photometry that includes the locally measured background for each star. However, when there is highly structures background and a crowded field, it may be desirable to only subtract a model of the fit stars from the image, without the local background estimate (that currently can only be a scalar). Otherwise we have overlapping regions of subtracted scalar backgrounds in the residual image when stars are close to each other.
This option may also be useful for iterative PSF fitting of clustered stars.
The solution would simply to add one more parameter ``include_bkg'' to both functions in the PSFPhotometry-class.

The changes should not break existing code, as far as I can tell.

Closes #1690

[larrybradley]

Thanks, @m-samland. I have just a few suggested changes.

[pep8speaks]

Hello @m-samland! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2024-02-12 15:27:58 UTC

[m-samland]

Thanks for the suggestions @larrybradley, I commited them. Happy to have this merged. :)

[larrybradley]

Thanks again, @m-samland. This needs a test and a changelog entry, but I'll add those in a followup PR. I'm also considering making the default be to not include the local background subtraction (unfortunately that would be a breaking change, but it might be sensible).

[SterlingYM]

Can the same feature (to turn off local bkg) be supported for IterativePSFPhotometry class too?

https://github.com/astropy/photutils/blob/d78f2acde625a8f526c99fd0fa021f52bfe7297f/photutils/psf/photometry.py#L1550C1-L1550C60

[larrybradley]

@SterlingYM Yes, I'll add that feature to IterativePSFPhotometry. Thanks!

[larrybradley]

@SterlingYM This was added in #1756.