<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Dear Francesco and Mario,<br>
<br>
FYI,<br>
While digesting the valuable information in your plots I already put
some of the material on the wiki in the KiDS-INT-DR2 cookbook area:<br>
<a class="moz-txt-link-freetext" href="http://wiki.astro-wise.org/projects:kids:data_deliveries:internaldelivery2.0_cookbook#kids_vs_sdss">http://wiki.astro-wise.org/projects:kids:data_deliveries:internaldelivery2.0_cookbook#kids_vs_sdss</a><br>
Hope this helps you as well and please have a look to improve my
wording if you find the time.<br>
<br>
Best wishes, Gijs<br>
<br>
<div class="moz-cite-prefix">Op 28-11-2012 10:21, Francesco La
Barbera schreef:<br>
</div>
<blockquote
cite="mid:CAOnmKXdxsq-8RhL+eMjforXCN8hKJ+KUOHWvLHAnMK2Zb0rs1A@mail.gmail.com"
type="cite">
<div>Dear All,</div>
<div><br>
</div>
<div>I summarize here the comparison of KIDS to SDSS
photometry we</div>
<div>(Mario+me) have performed so far for the 52 coadds of KIDS
INTR2. All</div>
<div>plots are included in the attached archive.</div>
<div><br>
</div>
<div>Mario has also performed a comparison to CFHTLS as well as
a first</div>
<div>attempt to characterize of color terms using SDSS and CFHTLS
data, but</div>
<div>I'm not going to include it in here (we didn't have much
time to look</div>
<div>at it in detail, so far).</div>
<div><br>
</div>
<div>We have matched the KIDSCAT catalogs to SDSS DR8, separating
stars and</div>
<div>galaxies according to SDSS classification.</div>
<div><br>
</div>
<div>The plots</div>
<div>
<br>
</div>
<div>sdss_${SOURCE}_${BAND}_${FIELD}_full_DR8.png </div>
<div><br>
</div>
<div>show differences in magnitude as a function of RA (upper
panel) and</div>
<div>DEC (lower panel), where </div>
<div>SOURCES -> gal/st refer to galaxies and stars,
respectively</div>
<div>BAND -> ugri</div>
<div>FIELD -> f135 plots the three fields with RA~131, 135, and
139</div>
<div> f185 plots the ten fields with RA~184, 185, and 186</div>
<div><br>
</div>
<div>We are using petromags from SDSS (for both stars and
galaxies).</div>
<div>KIDSCAT mags have been interpotaled to match the SDSS
4xPetroRad</div>
<div>(diameter) aperture for each object. Lines are running
medians for</div>
<div>different bands/pointings (the u-band comparison for galaxies
is quite</div>
<div>meaningless, considering the low S/N of SDSS u-band
data). Median</div>
<div>KIDS-SDSS offsets have been subtracted off for each field.</div>
<div><br>
</div>
<div>On average, the agreement is good, with no significant
variations</div>
<div>(larger than a few cenths of mags) across the fields. This
is further</div>
<div>shown in the attached plots</div>
<div><br>
</div>
<div>cmp_${BAND}band_phot_ra_dec_${SOURCES}_errmag0.05.jpg</div>
<div><br>
</div>
<div>where </div>
<div><br>
</div>
<div>BAND->ugri</div>
<div>SOURCES-> stars/galaxies</div>
<div><br>
</div>
<div>plotting magntiude differences as a function of RA and DEC
with all</div>
<div>fields overplotted (after subtracting off the RA and DEC of
each coadd</div>
<div>center). Median magnitude offsets have been removed (as
done for</div>
<div>previous plots), and only objects with better SDSS
photometry</div>
<div>(petroerr_mag<0.05mag) have been selected. Circles plot
all available</div>
<div>sources (for all 13 coadds in each band). Curves are
median-binned</div>
<div>trends (each bin including the same number of objects), with
different</div>
<div>colors corresponding to different fields. Notice that the
u-band plot</div>
<div>for galaxies is not included, for the reasons mentioned
above.</div>
<div><br>
</div>
<div>Finally, the plots </div>
<div><br>
</div>
<div>off_${BAND}band_phot_ra_dec_${SOURCES}_errmag0.05.jpg</div>
<div><br>
</div>
<div>show the distribution of median magnitude offsets for
all the 13</div>
<div>fields available in each band. In general, the
distributions have a</div>
<div>width of a few cenths of mags, but in one case
(KIDS_185.0_-0.5,</div>
<div>g-band) there is a large offset of ~0.1mag. We think it's
important to</div>
<div>investigate why this happened.</div>
<div><br>
</div>
<div>I'm also attaching two tables (produced by Mario, hopefully
in wiki</div>
<div>format) summarizing the the median offsets, mad, and peak
to peak</div>
<div>amplitudes in RA and DEC (to have an upper value to the
internal</div>
<div>photometric accuracy):</div>
<div><br>
</div>
<div>ov_sdss_gals.tab</div>
<div>ov_sdss_stars.tab</div>
<div><br>
</div>
<div>If necessary, I can provide further details/info on the
comparison</div>
<div>during today's teleconf. We'll try to put all this material
on the wiki as</div>
<div>soon as possible.</div>
<div><br>
</div>
<div>Cheers,</div>
<div>Francesco & Mario</div>
<div><br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
KiDS mailing list
<a class="moz-txt-link-abbreviated" href="mailto:KiDS@astro-wise.org">KiDS@astro-wise.org</a>
<a class="moz-txt-link-freetext" href="http://listman.astro-wise.org/mailman/listinfo/kids">http://listman.astro-wise.org/mailman/listinfo/kids</a></pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
--------------------------------------------------------------------
|dr Gijs Verdoes Kleijn | astronomer |
|e-mail: <a class="moz-txt-link-abbreviated" href="mailto:verdoes@astro.rug.nl">verdoes@astro.rug.nl</a> | OmegaCEN / Kapteyn Institute / |
|www: <a class="moz-txt-link-abbreviated" href="http://www.astro.rug.nl/~verdoes">www.astro.rug.nl/~verdoes</a> | Target |
|tel: +31-50-3638326 | University of Groningen |
|mobile: +31-654658050 | postal address: |
| | Kapteyn Astronomical Institute |
| | Postbus 800, 9700 AV, Groningen|
| | The Netherlands |
--------------------------------------------------------------------</pre>
</body>
</html>