Strange background flux around transients

[Astro-Sean]

Hi,

Getting nice results with your code - however I have a strange issue when recovering transient flux - the background around the transient is around 4x times less than the image.

I'm using the code snippet from the tutorial. Setting Beta=True gives these results, without it I get strange residuals of the host galaxy. Any helps would be much appreciated.

result = subtract( ref=ref, new=sci, smooth_psf=False, fitted_psf=True, align=False, iterative=False, beta=True, shift=False)

[BrunoSanchez]

Hi! This looks strange. It seems related to the background when the code measures the PSF. As if the PSF would tend to sit on a negative background or similar... What is the mask ourtput?

[pythonPleiades]

Hello. I'm having the same issue and mostly at galaxy cores and sometime at bright stars. Any help to minimize or remove those artifacts would be appreciated. Cheers.

[BrunoSanchez]

Hi, can you give me more details? What is the mask output? I am not actively working on the code for a long time, but would be nice to hear more about this problem.

Is it possible to get some reproducible case? can you tar images + script? Thanks

[pythonPleiades]

Hello Bruno. Thanks for the reply. Similar to Astro-Sean (previous message), I'm using the code from the tutorial: result = subtract( ref=ref, new=sci, smooth_psf=True, fitted_psf=True, align=False, iterative=False, beta=True, shift=False). I tried different subtraction options but similar results. Here the result with Scorr_diff from NGC 3556:

Most of the time, I get dark square with a bright star inside, at center. Here the mask result:

Here a copy of the Science and Reference files: NGC 3556_Reference.zip Thanks again for your help.