[bug #59726] MakeCatalog's --halfsumradius under estimates effective radius

[Mohammad Akhlaghi]

Follow-up Comment #1, bug #59726 (project gnuastro):

Nacho had a good suggestion to see the behavior at Sersic indices below 1 also
(to confirm the hypothesis). 

So I updated the input catalog to the one below (the Sersic index is the 6th
column: I also added Sersic index 4), with everything else identical. 


1 300 250 1 10 0.5  0 1 1 10
2 700 300 1 10 1    0 1 1 10
4 300 650 1 10 4    0 1 1 10
3 700 700 1 10 10   0 1 1 10


I then ran the same commands before. The resulting image can be seen attached
to this message. Here is the new catalog:


1      8.21       
2      8.33       
3      8.04       
4      5.86       


The fact that it hasn't changed between Sersic index of 0.5 and 1 is probably
due to the pixel size limit. It would probably be more clear at larger input
effective radii. But I was expecting a larger difference of measured effective
radius between Sersic index 1 and 4! 

I feel that using the elliptical distance instead of pixel counting can
improve this result. Let's see...

(file #50520)
    _______________________________________________________

Additional Item Attachment:

File name: profiles.png                   Size:34 KB
    <https://file.savannah.gnu.org/file/profiles.png?file_id=50520>



    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?59726>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/