[KIDS] completeness/contamination

Wed Feb 6 10:12:53 CET 2013

Hi Gert,

On Tue, Feb 5, 2013 at 4:54 PM, G. Sikkema <sikkema at astro.rug.nl> wrote:

>  hi Francesco,
>
> thanks for the analysis report on completeness for field KIDS_135_-1.5.
> We are currently reprocessing the g,r,i tiles, to see if we can remove the
> satellite tracks.
>
However, the new satellite code has problems removing very faint satellite
> tracks (at ~2 times the nosie).
>

OK, thanks for the update.

> So in my opinion, it would be good to set the detection threshold at least
> to 2 and min_area at 5.
> Could you also send the source distribution plots (i.e.:
> CONTAMINATION_xy_min3_thre2.0.jpg ) for the following configurations?:
> min_area=5 & detect_thresh=2.5
> min_area=5 & detect_thresh=2.0
> min_area=3 & detect_thresh=2.5
>
> And from what band was your source distrubtion plot derived?
>

Pls, find attached here the requested plots. I included all four cases
(min_area=3 and threshold=2.0), as I redid
the plots with a different color coding:
black -> all contaminants in the selected region
red     -> contaminants with S-Ex FLAGS=0
 blue  -> contaminants with S-Ex FLAGS between 1 and 3 (i.e. deblended
sources, and/or objects contaminated by close neighbors)

Also, all these plots refer to r band, as reported in the new filenames.

Cheers,
Francesco

GS
>
>
>
>
> On 02/05/2013 12:51 PM, Francesco La Barbera wrote:
>
> Dear All,
>
>  we performed a more detailed study of completeness/contamination of our
> KIDS catalogs by comparing
> KIDS vs. CFHT photometry in the field of KIDS_135_-1.5.
>
>  Here it's the steps we followed:
>
>  1) We downloaded the last version of the images, that   shouldn't be
> affected
> by the satellite track issue we found in the previous version of the
> coadd's.
>
> 1) We ran KIDSCAT on the r-band images, with 6 different setups, changing
> DETECTION_MINAREA
> and DETECTION_THRESHOLD in the S-Ex .configuration file. We considered:
> MINAREA: 3, 5
> THRESHOLD: 1.5, 2.0, 2.5
> Besides that, we also ran KIDSCAT on the g and i band images with
> MINAREA=3, and THRESHOLD=2.0, 2.5
>
>
>  2) The catalogs were matched to the CFHT ones (pls ask Mario for details)
>
>  3) The first attached plot, CFHT_KIDS_....._THRESHOLD.jpg, summarizes
> the completeness/contamination with different setups for the r-band coadd.
> Top and bottom panels correspond to MINAREA=3 and 5, respectively.
> For each panel, the solid curves plot the fraction of spurious sources
> (i.e. objects with no matching to CFHT)
> as a function of magnitude. We considered magnitudes in the same aperture
> of 5'' in both catalogs (KIDS and CFHT).
> Curves with different colors correspond to different DETECTION_THRESHOLDs
> as labeled.
> The completeness mags, for each THRESHOLD value (i.e. color), are marked
> with a vertical dashed line.
> (Here completeness is defined as the mag value where CFHT counts keep
> increasing, while KIDS counts remain constant/decrease).
>
>  4) The second attached plot shows the spatial distribution of spurious
> sources in the area "previously" affected by the satellite track.
>
>  5) We would conclude as follows:
>  A) for THRESHOLD=1.5 contamination increases significantly, up to ~20-22%
> around the completeness mag
>  B) completeness improves by ~0.15-0.2mag when moving from THRESHOLD 2.5
> to 2.0, and by the same amount from 2.0 to 1.5.
>  C) changing MINAREA to 5 we get slightly lower completeness
> (by~0.1-0.15mag), and slightly lower contamination (by a few percent)
>  D) the satellite track issue is still there
>
>  Depending on what is the maximum level of contamination we can allow in
> the catalogs, we think we might adopt either THRESHOLD=2.5 (current value)
> or THRESHOLD=2.0, as in the latter value we get slightly better
> completeness, at the price of a bit worst contamination.
> Notice that the contamination fractions are indeed upper limits (see our
> previous email on the subject), as there are many sources
> not present in the CFHT catalogs  because of (e.g.) deblending issues.
>
>  Finally, the last attached plot,
>   CFHT_KIDS_COMPLETENESS_CONTAMINATION_THRESHOLD_g_i_bands.jpg, shows
> completeness and contamination
> for g band (upper panel) and i band (lower panel), both for MINAREA=3.
> Resuts are similar to those for r band.
>
>  Eagerly waiting for your feedback, so that we can finalize the S-Ex
> configuration file.
>
>  Cheers,
> Francesco, Nicola, Mario
>
>
> -------------------------------------------------------------------------------
>
>
>
> _______________________________________________
> KiDS mailing listKiDS at astro-wise.orghttp://listman.astro-wise.org/mailman/listinfo/kids
>
>
>
> --
> dr. Gert Sikkema
>
> Kapteyn Institute
> Zernike Building, room 133
> P.O. Box 800
> 9700 AV Groningensikkema at astro.rug.nl
> homepage: http://www.astro.rug.nl/~sikkema
> 31-50-3634548
> MSN: add: cubensi at hotmail.com to your MSN
>
> * Popular lectures on:
> - Einstein's theory of Relativity
> - Globular Clusters
>
>
> _______________________________________________
> KiDS mailing list
> KiDS at astro-wise.org
> http://listman.astro-wise.org/mailman/listinfo/kids
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listman.astro-wise.org/pipermail/kids/attachments/20130206/4ca7dfc6/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CONTAMINATION_xy_min3_thre2.0_rband.jpg
Type: image/jpeg
Size: 242204 bytes
Desc: not available
Url : http://listman.astro-wise.org/pipermail/kids/attachments/20130206/4ca7dfc6/attachment-0004.jpg 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CONTAMINATION_xy_min3_thre2.5_rband.jpg
Type: image/jpeg
Size: 188446 bytes
Desc: not available
Url : http://listman.astro-wise.org/pipermail/kids/attachments/20130206/4ca7dfc6/attachment-0005.jpg 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CONTAMINATION_xy_min5_thre2.0_rband.jpg
Type: image/jpeg
Size: 214745 bytes
Desc: not available
Url : http://listman.astro-wise.org/pipermail/kids/attachments/20130206/4ca7dfc6/attachment-0006.jpg 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CONTAMINATION_xy_min5_thre2.5_rband.jpg
Type: image/jpeg
Size: 171903 bytes
Desc: not available
Url : http://listman.astro-wise.org/pipermail/kids/attachments/20130206/4ca7dfc6/attachment-0007.jpg 