Dark Energy Survey » Science Verification

h1. SVA1 Data Analysis

This wiki page will record information gleaned from the biweekly Monday SVA1 Analysis telecon.  In the end, this will build up a compilation of best-practices and systematics for different magnitudes; star/galaxy separation; photometric zeropoints; masking; etc.

h2. Telecon Information

Call-in instructions:

1. Dial Toll-Free Number: 866-740-1260 (U.S. & Canada)

2. International participants dial:

Toll Number: 303-248-0285

Or International Toll-Free Number: http://www.readytalk.com/intl

UK: 0800 496 0576

3. Enter your 7-digit access code, followed by “#”

Your access code: 7691719

[[Agenda And Minutes for 10/14, 10am CDT]]

[[Agenda And Minutes for 10/28, 10am CDT]]

[[Agenda And Minutes for 11/11, 10am CST]]

[[Agenda And Minutes for 11/25, 10am CST]]

[[Agenda And Minutes for 12/09, 10am CST]]

[[Agenda And Minutes for 12/18, 10am CST]]

[[Agenda And Minutes for 1/22, 10am CST]]

[[Agenda And Minutes for 2/3, 10am CST]]

[[Agenda And Minutes for 3/3, 10am CST]]

[[Agenda And Minutes for 3/17, 10am CDT]]

[[Agenda And Minutes for 3/31, 10am CDT]]

[[Agenda And Minutes for 4/14, 10am CDT]]

[[Agenda And Minutes for 4/28, 10am CDT]]

[[Agenda And Minutes for 5/12, 10am CDT]]

[[Agenda And Minutes for 6/9, 10am CDT]]

[[Agenda And Minutes for 6/23, 10am CDT]]

[[Agenda And Minutes for 7/21, 10am CDT]]

[[Agenda And Minutes for 8/4, 10am CDT]]

[[Agenda And Minutes for 8/18, 10am CDT]]

h2. Gold Catalog v1.0

The [[SVA1 Gold Catalog v1.0]] is described here.

[[Is something going wrong with errors on MAG_AUTO?]]

[[Odd magnitudes in ELG selection]]

h2. Completeness Tests

[[Testing Completeness with UFIG]]

[[Testing Completeness with Shallow SN Field Coadds]]

[[Galaxy Completeness Estimate with SN Field Coadds]]

h2. Astrometry

[[Relative Astrometry in SVA1 Finalcut]]

[[Fixing Astrometry in SVA1 Finalcut]]

[[Fixed Astrometry in SVA1 Finalcut]]

h2. Punch List

[[SVA1 Catalog Punch List]]

h2. Which Magnitudes?

DETMODEL for colors...

h2. Star/Galaxy Separation

The [[SG separation challenge]].

On this page, you can find some results of tests on the COSMOS field, including star/galaxy separation.

https://cdcvs.fnal.gov/redmine/projects/des-lss/wiki/Systematics_tests

Some studies on star/galaxy separation for final cut and coadd objects in the SN fields "S/G SVA1 SN fields":http://des-docdb.fnal.gov:8080/cgi-bin/ShowDocument?docid=7448

Some interesting spread model maps are at [[Spread Model Maps]]

and [[A Modest Proposal for Preliminary Star/Galaxy Separation]] (Eli)

with [[Bright Galaxy Impurity]]

and [[Bright Star Spread Model Issues]].

and [[Tile dependence of star-galaxy classification]]

and [[Tile dependence of PSF in the SN Field Coadds]]

Problematic issues when [[Comparing to Homogenized Coadds]]

And a follow up on [[Comparing Photometry to Homogenized Coadds]]

[[des-sci-verification:SVA1_Gold_v10_SG_Validation|Applying new SG classifiers to the whole SVA1 region]].

h2. Photometric Zeropoints

Currently, "Bob Armstrong's SLR zeropoints":https://cdcvs.fnal.gov/redmine/projects/descalibration/wiki/Stellar_Locus_Regression have been tested and work reasonably well, but "finer scale SLR":https://cdcvs.fnal.gov/redmine/projects/descalibration/wiki/Stellar_Locus_Regression_for_SVA1_on_HEALPix_Grid is being worked on.

h2. Survey Masks

On this page, you can find the links to Mangle info.

https://cdcvs.fnal.gov/redmine/projects/des-lss/wiki/SG1_infrastructure

[[Improved Gold 1.0 Depth Maps]]

[[Translating Mangle Masks Into Data Units]]

[[Galaxy depth and completeness using Mangle Mask]]

[[Sub-Pixelizing Mangle Masks]]

[[Testing Correlation Functions with Pixelized Mangle Masks]]

h2. SN Field Re-Coadds

[[SVA1 SN Field Shallow Coadds]]

h2. Cosmic ray rejection from catalogues

I might be useful to have the peak intensity value at xpeak, ypeak [Richard McMahon]

h2. Coadd catalogue objects provenance

Coadd catalogue provenance link to input catalogue files. It would be useful to have the source id from

the input catalog files

e.g.

DES0226-0416_r_cat.fits

TTYPE1  = 'NUMBER  '           / Running object number

This would allow joins between COADD_OBJECTS and OBJECTS_CURRENT and allow end-to-end checks.

OBJECTS_CURRENT has columns called:

OBJECT_ID,NUMBER,22,11,0,

OBJECT_NUMBER,NUMBER,22,6,0,

PARENTID,NUMBER,22,11,0,

h2. Coadd catalogue objects deblending information

It would be useful to know which objects are members of a blend so that one can

determine the magnitude difference and pairwise separattions so that the effect of

blending can be estimated. 

h2. Other DESDM COADD catalogues oddities

There are columns without the waveband identified 

RA

DEC

Image shape parameters

TTYPE8  = 'A_IMAGE '  

TTYPE8  = 'B_IMAGE '

THETA_IMAGE'

but we have THETA_IMAGE_[GRIZY] but not A_IMAGE, B_IMAGE

Ellipticity seem to be missing.

Fluxes

flux_psf values are in object catalogues but not in the coadd table

h2. Other Pages

[[Regions of Bad Photometry]]

[[Bad Photometry Maps]]

[[An Ugly Image]]

[[On the Bias Jumps]]

[[Some tests on depth with Mangle Mask]]

[[Tile dependence of star-galaxy classification]]

[[Tile dependence of PSF in the SN Field Coadds]]

Column documentation at DESDM users group wiki page:

https://cosmology.illinois.edu/confluence/display/DESDAF/Overview+of+data+columns+in+DESDB