2MASS Final Catalog Generation Test Fields
2MASS Final Catalog Generation Test Fields

Introduction

Several fields are selected to test final catalog generation algorithms, implementation and analysis.

Field Descriptions

**Catalog Generation Test Fields**
Name	ra0 (deg)	dec0 (deg)	N_dec_bands	Tiles
South1	75.0	-27.0	3	309418-309458,312218-312256,314900-314937
Equator1	90.0	+12.0	2	6665-6685,203721-203740
Equator2	283.3	+6.0	2	202340-202362,205306-205328
Polar1	-	90.0	1	29514-29824
0/0	0.0	0.0

South1

Large contiguous block of 118 southern tiles covering three bands of declination. All scans observed once with quality 10.
Equator1

Contiguous block of 41 tiles covering two declination bands, sampling data from both Mt. Hopkins and CTIO. In the Galactic Plane at l=196, so densities are moderate (~25,000 deg^-2). All scans observed once with quality 10.
Equator2

Contiguous block of 46 tiles covering two declination bands, sampling very high source density region in the Galactic Plane at l~+2^o. All scans observed once with quality 10.

Polar1

311 Tiles circling the north celestial pole. Eighteen Tiles have multiple scans of comparable "best" quality. The method used for selecting the 18 multiply-observed Tiles for the Catalog Generation Database is described here.

0/0

Field centered on 0^h meridian and celestial equator to test coordinate calculations.

Details and Statistics

South1 Equator1 Equator2 Polar1 0/0

Number of Scans: 118 41 46 311

Number of WDB Point Sources: 1205906 957267 3303690 3788450

Number of CatGen Point Sources: 250732 546030 2912796 848192

Number of WDB Extended Sources: 4498 1810 121 10217

Number of CatGen Extended Sources: 4135 1467 94 8589

List of Scans in Field X X X X

Map of K_s<13^m Sources in Galactic Coords
(red - R1-saturated in >1 bands; blue - R1-saturated in 3-bands) X X X X

Test Field FPG Status

South1 Equator1 Equator2 Polar1    0/0

Drawn from Working DB
(available in GATOR and rmt_grit)   X   X   X   X

Multiple Source Processing Complete
(use_src, dup_src, spos and sdet values set)   X   X   X   X

DB_MAPCOR Processing Complete
(prg_flg and cc_flg updated)   X   X   X   X

Extended Source Processing Complete
(cc_flg and vc values set)
  X   X   X   X

Proximity Analysis Complete
(prox and pxpa values set)

"Catalog" field set   X   X   X   X

Analysis Results

General

Duplicate Source Processing

Duplicate Source Analysis in V3 Processing (S. Wheelock - 1/28/02)
Nearest Neighbor Analysis and Duplicate Source Processing (R. Stiening - 3/27/02)

I have attached a plot that shows the distribution in nearest neighbor of
sources in the test fields (only sources with use_src=1 were used) where
the nearest neighbor was in a different scan.  The dup resolution
algorithm should have killed all neighbors in a different scan closer than
2" and indeed it has without exception.  I think I understand why the
distribution turns over at larger separations but do others agree?

Non-duplicate Sources vs. SNR (R. Stiening - 3/31/02)

I have attached two figure that may be useful a discussion of how sources
with use_src=0 and dup_src=0 (i.e. sources that are identified as not
having a matching source in an overlap region where that is geometrically
possible) should be treated in the catalog selection process.

Sherry has indicated that there is a bug in the dup resolution software
and the plots are made with data processed with the bug.  However, I don't
think the bug affects many sources.

I propose that sources not be rejected from the faint source list because
use_src=0 and dup-src=0 and that similar sources in the catalog region of
snr either be accepted as well or be placed in the faint source list.

Rae

Ghost-Kill Fraction vs. SNR

Ghost-Kill Fraction vs. SNR - expanded scale

A bug in the duplicate source resolution code was found that was inadvertantly dropping some non-duplicate sources that should be kept for the catalog. That bug was fixed and the duplicate resolution rerun. The following plots show the ghost kill-fractions after the bug fix. Rae reports: "It seems that the fix recovered a few more sources in the catalog region than in the faint source region."

Ghost-Kill Fraction vs. SNR (4/3/02)
Ghost-Kill Fraction vs. SNR - expanded scale (4/3/02)

Distance to nearest neighbors in use_src=dup_src=0 sources (R. Stiening - 4/9/02)

The nature of use_src=0 dup_src=0 sources with high SNR (M. Skrutskie - 4/16/02)

Artifact Flagging

DB_MAPCOR artifact flagging in the Test Fields (R. Tam and T. Evans - 5/10/02)

Point Source Count and Color Maps (J. Carpenter - 1/20/02)

Astrometry

Analysis of Overlap Positions in Catalog Test Fields (H. McCallon - 4/11/02)

Extended Sources

Extended Source Visual Classifications - (T. Jarrett - 1/20/02)

South1

Point Source Colors (M. Skrutskie 12/18/01)

Attached is a whirlgif which now shows
the (very nice) color-color/mag diagrams for the first cut query.  I'm blinking
between the entire selected set against a kludge in which I prevent the query 
from selecting the snr>5 in any one band faint sources.  You can see they fill 
in rather nicely.

Non-3-band Sources (M. Skrutskie 12/19/01)

Polar1

Duplicate-resolved Extended Source Distribution at the NCP (R. Stiening - 4/1/02)

I was curious about the bright spot in John Carpenter's plots near the
north equatorial pole.  Since the galaxy distribution is independent of
the star distribution I was curious about whether or not the galaxies
would show a bright spot as well.

NCP Dup-Resolved Galaxy Gatalog

(M. Skrutskie - 4/1/02)  John notes that the bright spot is NGC 188.  
I've attached the coadd image.  Since his is a star counts rather 
than a flux map the cluster really stands out.

J-Band Atlas Image in the vicinity of NGC188

Last Updated: 13 May 2002
R. Cutri - IPAC