Re: Regarding astsegment clump detection

[Mohammad Akhlaghi]

Hi Chandan,

Thanks for getting in touch.

What do you mean by "size" of clumps/PSF? Can you show your question on 
an image (highlighting with arrows/circles the size difference you are 
talking about)?

Just have in mind that by definition, clumps only cover high 
signal-to-noise pixels; see the following recorded presentations:

https://peertube.stream/w/stJ4er5Bx5SECg3kLTmXfC
https://peertube.stream/w/35b7c398-9fd7-4bcf-8911-1e01c5124585

Or the main papers:

https://arxiv.org/pdf/1505.01664.pdf
https://arxiv.org/pdf/1909.11230.pdf

Cheers,
Mohammad

On 10/19/23 11:32, chandan watts wrote:
> Hi,
>
> I have used the astsegment command to identify clumps in the DECaLS g-band
> image. I didn't specify any threshold limit in the astsegment command and
> detected the clumps, but most clumps have sizes less than the psf size of
> the image. I want to know if the astsegment task is detecting clumps having
> a size less than psf size of the image. Can these clumps be considered
> realistic or not?
>
> Regards,
> Chandan